From 46bf318fb031f48555ee78cc81a478c8d326d2d3 Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Wed, 9 Dec 2020 12:27:35 -0500
Subject: [PATCH 01/21] typing

---
 pandas/core/frame.py | 122 +++++++++++++++++++++++++++----------------
 1 file changed, 78 insertions(+), 44 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index fd7820196f9a9..819cf4fc60aff 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -22,12 +22,14 @@
     TYPE_CHECKING,
     Any,
     AnyStr,
+    Callable,
     Dict,
     FrozenSet,
     Hashable,
     Iterable,
     Iterator,
     List,
+    Mapping,
     Optional,
     Sequence,
     Set,
@@ -48,6 +50,7 @@
 from pandas._libs.lib import no_default
 from pandas._typing import (
     AggFuncType,
+    AnyArrayLike,
     ArrayLike,
     Axes,
     Axis,
@@ -59,6 +62,8 @@
     Label,
     Level,
     Renamer,
+    Scalar,
+    Shape,
     StorageOptions,
     ValueKeyFunc,
 )
@@ -643,7 +648,7 @@ def axes(self) -> List[Index]:
         return [self.index, self.columns]
 
     @property
-    def shape(self) -> Tuple[int, int]:
+    def shape(self) -> Shape:
         """
         Return a tuple representing the dimensionality of the DataFrame.
 
@@ -1071,7 +1076,9 @@ def iterrows(self) -> Iterable[Tuple[Label, Series]]:
             s = klass(v, index=columns, name=k)
             yield k, s
 
-    def itertuples(self, index: bool = True, name: Optional[str] = "Pandas"):
+    def itertuples(
+        self, index: bool = True, name: Optional[str] = "Pandas"
+    ) -> Iterable[Tuple]:
         """
         Iterate over DataFrame rows as namedtuples.
 
@@ -1161,7 +1168,7 @@ def __len__(self) -> int:
         """
         return len(self.index)
 
-    def dot(self, other):
+    def dot(self, other: Union[AnyArrayLike, DataFrame]) -> FrameOrSeriesUnion:
         """
         Compute the matrix multiplication between the DataFrame and other.
 
@@ -1271,13 +1278,13 @@ def dot(self, other):
         else:  # pragma: no cover
             raise TypeError(f"unsupported type: {type(other)}")
 
-    def __matmul__(self, other):
+    def __matmul__(self, other: Union[AnyArrayLike, DataFrame]) -> FrameOrSeriesUnion:
         """
         Matrix multiplication using binary `@` operator in Python>=3.5.
         """
         return self.dot(other)
 
-    def __rmatmul__(self, other):
+    def __rmatmul__(self, other: Union[AnyArrayLike, DataFrame]) -> FrameOrSeriesUnion:
         """
         Matrix multiplication using binary `@` operator in Python>=3.5.
         """
@@ -1294,7 +1301,13 @@ def __rmatmul__(self, other):
     # IO methods (to / from other formats)
 
     @classmethod
-    def from_dict(cls, data, orient="columns", dtype=None, columns=None) -> DataFrame:
+    def from_dict(
+        cls,
+        data,
+        orient: str = "columns",
+        dtype: Optional[Dtype] = None,
+        columns: Optional[List] = None,
+    ) -> DataFrame:
         """
         Construct DataFrame from dict of array-like or dicts.
 
@@ -1373,7 +1386,10 @@ def from_dict(cls, data, orient="columns", dtype=None, columns=None) -> DataFram
         return cls(data, index=index, columns=columns, dtype=dtype)
 
     def to_numpy(
-        self, dtype=None, copy: bool = False, na_value=lib.no_default
+        self,
+        dtype: Optional[Dtype] = None,
+        copy: bool = False,
+        na_value: Scalar = lib.no_default,
     ) -> np.ndarray:
         """
         Convert the DataFrame to a NumPy array.
@@ -1440,7 +1456,7 @@ def to_numpy(
 
         return result
 
-    def to_dict(self, orient="dict", into=dict):
+    def to_dict(self, orient: str = "dict", into=dict) -> Union[Dict, List, Mapping]:
         """
         Convert the DataFrame to a dictionary.
 
@@ -1615,15 +1631,15 @@ def to_dict(self, orient="dict", into=dict):
 
     def to_gbq(
         self,
-        destination_table,
-        project_id=None,
-        chunksize=None,
-        reauth=False,
-        if_exists="fail",
-        auth_local_webserver=False,
-        table_schema=None,
-        location=None,
-        progress_bar=True,
+        destination_table: str,
+        project_id: Optional[str] = None,
+        chunksize: Optional[int] = None,
+        reauth: bool = False,
+        if_exists: str = "fail",
+        auth_local_webserver: bool = False,
+        table_schema: Optional[List[Dict]] = None,
+        location: Optional[str] = None,
+        progress_bar: bool = True,
         credentials=None,
     ) -> None:
         """
@@ -2478,25 +2494,25 @@ def to_html(
         buf=None,
         columns=None,
         col_space=None,
-        header=True,
-        index=True,
+        header: bool = True,
+        index: bool = True,
         na_rep="NaN",
         formatters=None,
         float_format=None,
         sparsify=None,
-        index_names=True,
+        index_names: bool = True,
         justify=None,
         max_rows=None,
         max_cols=None,
-        show_dimensions=False,
+        show_dimensions: bool = False,
         decimal=".",
-        bold_rows=True,
+        bold_rows: bool = True,
         classes=None,
-        escape=True,
-        notebook=False,
-        border=None,
-        table_id=None,
-        render_links=False,
+        escape: bool = True,
+        notebook: bool = False,
+        border: Optional[int] = None,
+        table_id: Optional[str] = None,
+        render_links: bool = False,
         encoding=None,
     ):
         """
@@ -2708,7 +2724,7 @@ def info(
             show_counts=show_counts,
         )
 
-    def memory_usage(self, index=True, deep=False) -> Series:
+    def memory_usage(self, index: bool = True, deep: bool = False) -> Series:
         """
         Return the memory usage of each column in bytes.
 
@@ -2931,7 +2947,7 @@ def T(self) -> DataFrame:
     # ----------------------------------------------------------------------
     # Indexing Methods
 
-    def _ixs(self, i: int, axis: int = 0):
+    def _ixs(self, i: int, axis: Axis = 0):
         """
         Parameters
         ----------
@@ -3108,7 +3124,7 @@ def _getitem_multilevel(self, key):
             # loc is neither a slice nor ndarray, so must be an int
             return self._ixs(loc, axis=1)
 
-    def _get_value(self, index, col, takeable: bool = False):
+    def _get_value(self, index, col, takeable: bool = False) -> Scalar:
         """
         Quickly retrieve single value at passed column and index.
 
@@ -3224,7 +3240,7 @@ def _iset_item(self, loc: int, value):
         if len(self):
             self._check_setitem_copy()
 
-    def _set_item(self, key, value):
+    def _set_item(self, key, value) -> None:
         """
         Add series to DataFrame in specified column.
 
@@ -3243,7 +3259,7 @@ def _set_item(self, key, value):
         if len(self):
             self._check_setitem_copy()
 
-    def _set_value(self, index, col, value, takeable: bool = False):
+    def _set_value(self, index, col, value: Scalar, takeable: bool = False) -> None:
         """
         Put single value at passed column and index.
 
@@ -3276,7 +3292,7 @@ def _set_value(self, index, col, value, takeable: bool = False):
                 self.loc[index, col] = value
             self._item_cache.pop(col, None)
 
-    def _ensure_valid_index(self, value):
+    def _ensure_valid_index(self, value) -> None:
         """
         Ensure that if we don't have an index, that we can create one from the
         passed value.
@@ -3311,7 +3327,7 @@ def _box_col_values(self, values, loc: int) -> Series:
     # ----------------------------------------------------------------------
     # Unsorted
 
-    def query(self, expr, inplace=False, **kwargs):
+    def query(self, expr: str, inplace: bool = False, **kwargs) -> Optional[DataFrame]:
         """
         Query the columns of a DataFrame with a boolean expression.
 
@@ -3472,10 +3488,13 @@ def query(self, expr, inplace=False, **kwargs):
 
         if inplace:
             self._update_inplace(result)
+            return None
         else:
             return result
 
-    def eval(self, expr, inplace=False, **kwargs):
+    def eval(
+        self, expr: str, inplace: bool = False, **kwargs
+    ) -> Optional[Union[AnyArrayLike, Scalar]]:
         """
         Evaluate a string describing operations on DataFrame columns.
 
@@ -3732,7 +3751,7 @@ def extract_unique_dtypes_from_dtypes_set(
 
         return self.iloc[:, keep_these.values]
 
-    def insert(self, loc, column, value, allow_duplicates=False) -> None:
+    def insert(self, loc: int, column, value, allow_duplicates: bool = False) -> None:
         """
         Insert column into DataFrame at specified location.
 
@@ -3846,7 +3865,7 @@ def assign(self, **kwargs) -> DataFrame:
             data[k] = com.apply_if_callable(v, data)
         return data
 
-    def _sanitize_column(self, key, value, broadcast=True):
+    def _sanitize_column(self, key, value, broadcast: bool = True) -> np.ndarray:
         """
         Ensures new columns (which go into the BlockManager as new blocks) are
         always copied and converted into an array.
@@ -3954,7 +3973,7 @@ def reindexer(value):
         return np.atleast_2d(np.asarray(value))
 
     @property
-    def _series(self):
+    def _series(self) -> "Dict[int, Series]":
         return {
             item: Series(
                 self._mgr.iget(idx), index=self.index, name=item, fastpath=True
@@ -3962,7 +3981,9 @@ def _series(self):
             for idx, item in enumerate(self.columns)
         }
 
-    def lookup(self, row_labels, col_labels) -> np.ndarray:
+    def lookup(
+        self, row_labels: Sequence[Label], col_labels: Sequence[Label]
+    ) -> np.ndarray:
         """
         Label-based "fancy indexing" function for DataFrame.
         Given equal-length arrays of row and column labels, return an
@@ -4109,7 +4130,7 @@ def align(
         join="outer",
         axis=None,
         level=None,
-        copy=True,
+        copy: bool = True,
         fill_value=None,
         method=None,
         limit=None,
@@ -5912,7 +5933,9 @@ def nsmallest(self, n, columns, keep="first") -> DataFrame:
             self, n=n, keep=keep, columns=columns
         ).nsmallest()
 
-    def swaplevel(self, i=-2, j=-1, axis=0) -> DataFrame:
+    def swaplevel(
+        self, i: Union[int, str] = -2, j: Union[int, str] = -1, axis: Axis = 0
+    ) -> DataFrame:
         """
         Swap levels i and j in a MultiIndex on a particular axis.
 
@@ -5943,7 +5966,9 @@ def swaplevel(self, i=-2, j=-1, axis=0) -> DataFrame:
             result.columns = result.columns.swaplevel(i, j)
         return result
 
-    def reorder_levels(self, order, axis=0) -> DataFrame:
+    def reorder_levels(
+        self, order: Union[List[int], List[str]], axis: Axis = 0
+    ) -> DataFrame:
         """
         Rearrange index levels using input order. May not drop or duplicate levels.
 
@@ -6234,7 +6259,11 @@ def compare(
         )
 
     def combine(
-        self, other: DataFrame, func, fill_value=None, overwrite=True
+        self,
+        other: DataFrame,
+        func: Callable,
+        fill_value: Optional[Scalar] = None,
+        overwrite: bool = True,
     ) -> DataFrame:
         """
         Perform column-wise combine with another DataFrame.
@@ -6462,7 +6491,12 @@ def combiner(x, y):
         return self.combine(other, combiner, overwrite=False)
 
     def update(
-        self, other, join="left", overwrite=True, filter_func=None, errors="ignore"
+        self,
+        other,
+        join: str = "left",
+        overwrite: bool = True,
+        filter_func: Optional[Callable] = None,
+        errors: str = "ignore",
     ) -> None:
         """
         Modify in place using non-NA values from another DataFrame.

From eba7251938e8bbfd244586608cc487a4d45d926a Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Fri, 11 Dec 2020 15:54:37 -0500
Subject: [PATCH 02/21] typing

---
 pandas/core/frame.py | 68 ++++++++++++++++++++++++++++++--------------
 1 file changed, 46 insertions(+), 22 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 819cf4fc60aff..4dfdd8bf29e2a 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -6023,7 +6023,7 @@ def _arith_method(self, other, op):
 
     _logical_method = _arith_method
 
-    def _dispatch_frame_op(self, right, func, axis: Optional[int] = None):
+    def _dispatch_frame_op(self, right, func: Callable, axis: Optional[int] = None):
         """
         Evaluate the frame operation func(left, right) by evaluating
         column-by-column, dispatching to the Series implementation.
@@ -6104,7 +6104,7 @@ def _arith_op(left, right):
         new_data = self._dispatch_frame_op(other, _arith_op)
         return new_data
 
-    def _construct_result(self, result) -> DataFrame:
+    def _construct_result(self, result: DataFrame) -> DataFrame:
         """
         Wrap the result of an arithmetic, comparison, or logical operation.
 
@@ -6735,8 +6735,8 @@ def update(
     def groupby(
         self,
         by=None,
-        axis=0,
-        level=None,
+        axis: int = 0,
+        level: Optional[Level] = None,
         as_index: bool = True,
         sort: bool = True,
         group_keys: bool = True,
@@ -7067,12 +7067,12 @@ def pivot_table(
         values=None,
         index=None,
         columns=None,
-        aggfunc="mean",
+        aggfunc: AggFuncType = "mean",
         fill_value=None,
-        margins=False,
-        dropna=True,
+        margins: bool = False,
+        dropna: bool = True,
         margins_name="All",
-        observed=False,
+        observed: bool = False,
     ) -> DataFrame:
         from pandas.core.reshape.pivot import pivot_table
 
@@ -7089,7 +7089,7 @@ def pivot_table(
             observed=observed,
         )
 
-    def stack(self, level=-1, dropna=True):
+    def stack(self, level: Union[int, str, List] = -1, dropna: bool = True):
         """
         Stack the prescribed level(s) from columns to index.
 
@@ -7338,7 +7338,7 @@ def explode(
 
         return result
 
-    def unstack(self, level=-1, fill_value=None):
+    def unstack(self, level: Level = -1, fill_value=None):
         """
         Pivot a level of the (necessarily hierarchical) index labels.
 
@@ -7409,7 +7409,7 @@ def melt(
         var_name=None,
         value_name="value",
         col_level=None,
-        ignore_index=True,
+        ignore_index: bool = True,
     ) -> DataFrame:
 
         return melt(
@@ -7670,7 +7670,15 @@ def transform(
         assert isinstance(result, DataFrame)
         return result
 
-    def apply(self, func, axis=0, raw=False, result_type=None, args=(), **kwds):
+    def apply(
+        self,
+        func: Callable,
+        axis: Axis = 0,
+        raw: bool = False,
+        result_type: Optional[str] = None,
+        args: Tuple = (),
+        **kwds,
+    ):
         """
         Apply a function along an axis of the DataFrame.
 
@@ -7815,7 +7823,7 @@ def apply(self, func, axis=0, raw=False, result_type=None, args=(), **kwds):
         )
         return op.get_result()
 
-    def applymap(self, func, na_action: Optional[str] = None) -> DataFrame:
+    def applymap(self, func: Callable, na_action: Optional[str] = None) -> DataFrame:
         """
         Apply a function to a Dataframe elementwise.
 
@@ -7895,7 +7903,11 @@ def infer(x):
     # Merging / joining methods
 
     def append(
-        self, other, ignore_index=False, verify_integrity=False, sort=False
+        self,
+        other,
+        ignore_index: bool = False,
+        verify_integrity: bool = False,
+        sort: bool = False,
     ) -> DataFrame:
         """
         Append rows of `other` to the end of caller, returning a new object.
@@ -8036,7 +8048,13 @@ def append(
         ).__finalize__(self, method="append")
 
     def join(
-        self, other, on=None, how="left", lsuffix="", rsuffix="", sort=False
+        self,
+        other,
+        on=None,
+        how: str = "left",
+        lsuffix: str = "",
+        rsuffix: str = "",
+        sort: bool = False,
     ) -> DataFrame:
         """
         Join columns of another DataFrame.
@@ -8160,7 +8178,13 @@ def join(
         )
 
     def _join_compat(
-        self, other, on=None, how="left", lsuffix="", rsuffix="", sort=False
+        self,
+        other,
+        on=None,
+        how: str = "left",
+        lsuffix: str = "",
+        rsuffix: str = "",
+        sort: bool = False,
     ):
         from pandas.core.reshape.concat import concat
         from pandas.core.reshape.merge import merge
@@ -8226,16 +8250,16 @@ def _join_compat(
     def merge(
         self,
         right,
-        how="inner",
+        how: str = "inner",
         on=None,
         left_on=None,
         right_on=None,
-        left_index=False,
-        right_index=False,
-        sort=False,
+        left_index: bool = False,
+        right_index: bool = False,
+        sort: bool = False,
         suffixes=("_x", "_y"),
-        copy=True,
-        indicator=False,
+        copy: bool = True,
+        indicator: bool = False,
         validate=None,
     ) -> DataFrame:
         from pandas.core.reshape.merge import merge

From 1a452677044f28448ffef60b143b94a83a05bfd8 Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Fri, 11 Dec 2020 16:27:44 -0500
Subject: [PATCH 03/21] typing

---
 pandas/core/frame.py | 79 ++++++++++++++++++++++++++++----------------
 1 file changed, 51 insertions(+), 28 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 4dfdd8bf29e2a..ef31bef9f01b9 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -59,6 +59,7 @@
     FilePathOrBuffer,
     FrameOrSeriesUnion,
     IndexKeyFunc,
+    IndexLabel,
     Label,
     Level,
     Renamer,
@@ -1744,8 +1745,8 @@ def from_records(
         index=None,
         exclude=None,
         columns=None,
-        coerce_float=False,
-        nrows=None,
+        coerce_float: bool = False,
+        nrows: Optional[bool] = None,
     ) -> DataFrame:
         """
         Convert structured or record ndarray to DataFrame.
@@ -3259,7 +3260,9 @@ def _set_item(self, key, value) -> None:
         if len(self):
             self._check_setitem_copy()
 
-    def _set_value(self, index, col, value: Scalar, takeable: bool = False) -> None:
+    def _set_value(
+        self, index: int, col, value: Scalar, takeable: bool = False
+    ) -> None:
         """
         Put single value at passed column and index.
 
@@ -4216,12 +4219,12 @@ def reindex(self, *args, **kwargs) -> DataFrame:
     def drop(
         self,
         labels=None,
-        axis=0,
-        index=None,
+        axis: Axis = 0,
+        index: IndexLabel = None,
         columns=None,
-        level=None,
-        inplace=False,
-        errors="raise",
+        level: Level = None,
+        inplace: bool = False,
+        errors: str = "raise",
     ):
         """
         Drop specified labels from rows or columns.
@@ -5515,8 +5518,8 @@ def sort_values(  # type: ignore[override]
 
     def sort_index(
         self,
-        axis=0,
-        level=None,
+        axis: Axis = 0,
+        level: Level = None,
         ascending: bool = True,
         inplace: bool = False,
         kind: str = "quicksort",
@@ -7070,7 +7073,7 @@ def pivot_table(
         aggfunc: AggFuncType = "mean",
         fill_value=None,
         margins: bool = False,
-        dropna: bool = True,
+        dropna=True,
         margins_name="All",
         observed: bool = False,
     ) -> DataFrame:
@@ -7089,7 +7092,7 @@ def pivot_table(
             observed=observed,
         )
 
-    def stack(self, level: Union[int, str, List] = -1, dropna: bool = True):
+    def stack(self, level: Level = -1, dropna: bool = True):
         """
         Stack the prescribed level(s) from columns to index.
 
@@ -7616,7 +7619,7 @@ def _gotitem(
         see_also=_agg_summary_and_see_also_doc,
         examples=_agg_examples_doc,
     )
-    def aggregate(self, func=None, axis=0, *args, **kwargs):
+    def aggregate(self, func=None, axis: Axis = 0, *args, **kwargs):
         axis = self._get_axis_number(axis)
 
         relabeling, func, columns, order = reconstruct_func(func, **kwargs)
@@ -8260,7 +8263,7 @@ def merge(
         suffixes=("_x", "_y"),
         copy: bool = True,
         indicator: bool = False,
-        validate=None,
+        validate: Optional[str] = None,
     ) -> DataFrame:
         from pandas.core.reshape.merge import merge
 
@@ -8280,7 +8283,9 @@ def merge(
             validate=validate,
         )
 
-    def round(self, decimals=0, *args, **kwargs) -> DataFrame:
+    def round(
+        self, decimals: Union[int, Dict, Series] = 0, *args, **kwargs
+    ) -> DataFrame:
         """
         Round a DataFrame to a variable number of decimal places.
 
@@ -8394,7 +8399,9 @@ def _series_round(s, decimals):
     # ----------------------------------------------------------------------
     # Statistical methods, etc.
 
-    def corr(self, method="pearson", min_periods=1) -> DataFrame:
+    def corr(
+        self, method: Union[str, Callable] = "pearson", min_periods: int = 1
+    ) -> DataFrame:
         """
         Compute pairwise correlation of columns, excluding NA/null values.
 
@@ -8601,7 +8608,13 @@ def cov(
 
         return self._constructor(base_cov, index=idx, columns=cols)
 
-    def corrwith(self, other, axis=0, drop=False, method="pearson") -> Series:
+    def corrwith(
+        self,
+        other: FrameOrSeriesUnion,
+        axis: Axis = 0,
+        drop: bool = False,
+        method: Union[str, Callable] = "pearson",
+    ) -> Series:
         """
         Compute pairwise correlation.
 
@@ -8851,9 +8864,9 @@ def _reduce(
         op,
         name: str,
         *,
-        axis=0,
-        skipna=True,
-        numeric_only=None,
+        axis: Axis = 0,
+        skipna: bool = True,
+        numeric_only: Optional[bool] = None,
         filter_type=None,
         **kwds,
     ):
@@ -8959,7 +8972,7 @@ def _get_data() -> DataFrame:
         result = self._constructor_sliced(result, index=labels)
         return result
 
-    def nunique(self, axis=0, dropna=True) -> Series:
+    def nunique(self, axis: Axis = 0, dropna: bool = True) -> Series:
         """
         Count distinct observations over requested axis.
 
@@ -8999,7 +9012,7 @@ def nunique(self, axis=0, dropna=True) -> Series:
         """
         return self.apply(Series.nunique, axis=axis, dropna=dropna)
 
-    def idxmin(self, axis=0, skipna=True) -> Series:
+    def idxmin(self, axis: Axis = 0, skipna: bool = True) -> Series:
         """
         Return index of first occurrence of minimum over requested axis.
 
@@ -9076,7 +9089,7 @@ def idxmin(self, axis=0, skipna=True) -> Series:
         result = [index[i] if i >= 0 else np.nan for i in indices]
         return self._constructor_sliced(result, index=self._get_agg_axis(axis))
 
-    def idxmax(self, axis=0, skipna=True) -> Series:
+    def idxmax(self, axis: Axis = 0, skipna: bool = True) -> Series:
         """
         Return index of first occurrence of maximum over requested axis.
 
@@ -9164,7 +9177,9 @@ def _get_agg_axis(self, axis_num: int) -> Index:
         else:
             raise ValueError(f"Axis must be 0 or 1 (got {repr(axis_num)})")
 
-    def mode(self, axis=0, numeric_only=False, dropna=True) -> DataFrame:
+    def mode(
+        self, axis: Axis = 0, numeric_only: bool = False, dropna: bool = True
+    ) -> DataFrame:
         """
         Get the mode(s) of each element along the selected axis.
 
@@ -9251,7 +9266,9 @@ def f(s):
 
         return data.apply(f, axis=axis)
 
-    def quantile(self, q=0.5, axis=0, numeric_only=True, interpolation="linear"):
+    def quantile(
+        self, q=0.5, axis: Axis = 0, numeric_only: bool = True, interpolation="linear"
+    ) -> FrameOrSeriesUnion:
         """
         Return values at the given quantile over requested axis.
 
@@ -9348,7 +9365,11 @@ def quantile(self, q=0.5, axis=0, numeric_only=True, interpolation="linear"):
         return result
 
     def to_timestamp(
-        self, freq=None, how: str = "start", axis: Axis = 0, copy: bool = True
+        self,
+        freq: Optional[str] = None,
+        how: str = "start",
+        axis: Axis = 0,
+        copy: bool = True,
     ) -> DataFrame:
         """
         Cast to DatetimeIndex of timestamps, at *beginning* of period.
@@ -9381,7 +9402,9 @@ def to_timestamp(
         setattr(new_obj, axis_name, new_ax)
         return new_obj
 
-    def to_period(self, freq=None, axis: Axis = 0, copy: bool = True) -> DataFrame:
+    def to_period(
+        self, freq: Optional[str] = None, axis: Axis = 0, copy: bool = True
+    ) -> DataFrame:
         """
         Convert DataFrame from DatetimeIndex to PeriodIndex.
 
@@ -9413,7 +9436,7 @@ def to_period(self, freq=None, axis: Axis = 0, copy: bool = True) -> DataFrame:
         setattr(new_obj, axis_name, new_ax)
         return new_obj
 
-    def isin(self, values) -> DataFrame:
+    def isin(self, values: Union[FrameOrSeriesUnion, Dict, Iterable]) -> DataFrame:
         """
         Whether each element in the DataFrame is contained in values.
 

From f5cb185b565766a5192724f9310613f1dfd1beda Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Fri, 11 Dec 2020 16:36:15 -0500
Subject: [PATCH 04/21] typing

---
 pandas/core/reshape/pivot.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/reshape/pivot.py b/pandas/core/reshape/pivot.py
index 40496a5b8671b..7aa4bcf6fad62 100644
--- a/pandas/core/reshape/pivot.py
+++ b/pandas/core/reshape/pivot.py
@@ -612,7 +612,7 @@ def crosstab(
         margins=margins,
         margins_name=margins_name,
         dropna=dropna,
-        **kwargs,
+        **kwargs,  # type: ignore[arg-type]
     )
 
     # GH18321, after pivoting, an extra top level of column index of `__dummy__` is

From 4c9b7644a90ad1799ace742e84c32979997bcaec Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Fri, 11 Dec 2020 17:02:57 -0500
Subject: [PATCH 05/21] review comments

---
 pandas/core/frame.py | 40 ++++++++++++++++++++++------------------
 1 file changed, 22 insertions(+), 18 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index ef31bef9f01b9..8b9727939df0b 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -64,7 +64,6 @@
     Level,
     Renamer,
     Scalar,
-    Shape,
     StorageOptions,
     ValueKeyFunc,
 )
@@ -649,7 +648,7 @@ def axes(self) -> List[Index]:
         return [self.index, self.columns]
 
     @property
-    def shape(self) -> Shape:
+    def shape(self) -> Tuple[int, int]:
         """
         Return a tuple representing the dimensionality of the DataFrame.
 
@@ -4091,7 +4090,7 @@ def _reindex_columns(
         new_columns,
         method,
         copy,
-        level,
+        level: Level,
         fill_value=None,
         limit=None,
         tolerance=None,
@@ -4130,15 +4129,15 @@ def _reindex_multi(self, axes, copy, fill_value) -> DataFrame:
     def align(
         self,
         other,
-        join="outer",
-        axis=None,
-        level=None,
+        join: str = "outer",
+        axis: Optional[Axis] = None,
+        level: Optional[Level] = None,
         copy: bool = True,
         fill_value=None,
-        method=None,
-        limit=None,
-        fill_axis=0,
-        broadcast_axis=None,
+        method: Optional[str] = None,
+        limit: Optional[int] = None,
+        fill_axis: Axis = 0,
+        broadcast_axis: Optional[Axis] = None,
     ) -> DataFrame:
         return super().align(
             other,
@@ -4494,10 +4493,10 @@ def rename(
     def fillna(
         self,
         value=None,
-        method=None,
-        axis=None,
-        inplace=False,
-        limit=None,
+        method: Optional[str] = None,
+        axis: Optional[Axis] = None,
+        inplace: bool = False,
+        limit: Optional[int] = None,
         downcast=None,
     ) -> Optional[DataFrame]:
         return super().fillna(
@@ -4557,9 +4556,9 @@ def replace(
         self,
         to_replace=None,
         value=None,
-        inplace=False,
+        inplace: bool = False,
         limit=None,
-        regex=False,
+        regex: bool = False,
         method="pad",
     ):
         return super().replace(
@@ -4608,7 +4607,7 @@ def _replace_columnwise(
 
     @doc(NDFrame.shift, klass=_shared_doc_kwargs["klass"])
     def shift(
-        self, periods=1, freq=None, axis=0, fill_value=lib.no_default
+        self, periods: int = 1, freq=None, axis: Axis = 0, fill_value=lib.no_default
     ) -> DataFrame:
         axis = self._get_axis_number(axis)
 
@@ -4640,7 +4639,12 @@ def shift(
         )
 
     def set_index(
-        self, keys, drop=True, append=False, inplace=False, verify_integrity=False
+        self,
+        keys,
+        drop: bool = True,
+        append: bool = False,
+        inplace: bool = False,
+        verify_integrity: bool = False,
     ):
         """
         Set the DataFrame index using existing columns.

From a273e5c91b6d7ddcf1b4e2e7d4bb2bd1e60f5919 Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Sun, 13 Dec 2020 00:53:40 -0500
Subject: [PATCH 06/21] review comment

---
 pandas/core/frame.py | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 8b9727939df0b..733fe18b3b4ee 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -1168,7 +1168,7 @@ def __len__(self) -> int:
         """
         return len(self.index)
 
-    def dot(self, other: Union[AnyArrayLike, DataFrame]) -> FrameOrSeriesUnion:
+    def dot(self, other: Union[AnyArrayLike, FrameOrSeriesUnion]) -> FrameOrSeriesUnion:
         """
         Compute the matrix multiplication between the DataFrame and other.
 
@@ -1278,13 +1278,17 @@ def dot(self, other: Union[AnyArrayLike, DataFrame]) -> FrameOrSeriesUnion:
         else:  # pragma: no cover
             raise TypeError(f"unsupported type: {type(other)}")
 
-    def __matmul__(self, other: Union[AnyArrayLike, DataFrame]) -> FrameOrSeriesUnion:
+    def __matmul__(
+        self, other: Union[AnyArrayLike, FrameOrSeriesUnion]
+    ) -> FrameOrSeriesUnion:
         """
         Matrix multiplication using binary `@` operator in Python>=3.5.
         """
         return self.dot(other)
 
-    def __rmatmul__(self, other: Union[AnyArrayLike, DataFrame]) -> FrameOrSeriesUnion:
+    def __rmatmul__(
+        self, other: Union[AnyArrayLike, FrameOrSeriesUnion]
+    ) -> FrameOrSeriesUnion:
         """
         Matrix multiplication using binary `@` operator in Python>=3.5.
         """

From e0558c53325143e5d41c686e1c33d825b96459a9 Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Sun, 13 Dec 2020 01:00:57 -0500
Subject: [PATCH 07/21] review comment

---
 pandas/core/frame.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 733fe18b3b4ee..8ded800e67234 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -1310,7 +1310,7 @@ def from_dict(
         data,
         orient: str = "columns",
         dtype: Optional[Dtype] = None,
-        columns: Optional[List] = None,
+        columns: Optional[List[Label]] = None,
     ) -> DataFrame:
         """
         Construct DataFrame from dict of array-like or dicts.

From 617e2284f56cb98a090be35a4de9d3b2e1df3caf Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Mon, 14 Dec 2020 12:57:14 -0500
Subject: [PATCH 08/21] revert hints to pivot_table

---
 pandas/core/frame.py         | 6 +++---
 pandas/core/reshape/pivot.py | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 6aa755ac8ecc2..db3dab385782f 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -7092,12 +7092,12 @@ def pivot_table(
         values=None,
         index=None,
         columns=None,
-        aggfunc: AggFuncType = "mean",
+        aggfunc="mean",
         fill_value=None,
-        margins: bool = False,
+        margins=False,
         dropna=True,
         margins_name="All",
-        observed: bool = False,
+        observed=False,
     ) -> DataFrame:
         from pandas.core.reshape.pivot import pivot_table
 
diff --git a/pandas/core/reshape/pivot.py b/pandas/core/reshape/pivot.py
index 7aa4bcf6fad62..40496a5b8671b 100644
--- a/pandas/core/reshape/pivot.py
+++ b/pandas/core/reshape/pivot.py
@@ -612,7 +612,7 @@ def crosstab(
         margins=margins,
         margins_name=margins_name,
         dropna=dropna,
-        **kwargs,  # type: ignore[arg-type]
+        **kwargs,
     )
 
     # GH18321, after pivoting, an extra top level of column index of `__dummy__` is

From 9a4d187fd0a5a1d175e97d1cff6d13ea61cb2558 Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Mon, 14 Dec 2020 13:56:47 -0500
Subject: [PATCH 09/21] take out merge

---
 pandas/core/frame.py | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index db3dab385782f..f7d4bc4024614 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -8200,10 +8200,10 @@ def _join_compat(
         self,
         other,
         on=None,
-        how: str = "left",
-        lsuffix: str = "",
-        rsuffix: str = "",
-        sort: bool = False,
+        how="left",
+        lsuffix="",
+        rsuffix="",
+        sort=False,
     ):
         from pandas.core.reshape.concat import concat
         from pandas.core.reshape.merge import merge
@@ -8269,17 +8269,17 @@ def _join_compat(
     def merge(
         self,
         right,
-        how: str = "inner",
+        how="inner",
         on=None,
         left_on=None,
         right_on=None,
-        left_index: bool = False,
-        right_index: bool = False,
-        sort: bool = False,
+        left_index=False,
+        right_index=False,
+        sort=False,
         suffixes=("_x", "_y"),
-        copy: bool = True,
-        indicator: bool = False,
-        validate: Optional[str] = None,
+        copy=True,
+        indicator=False,
+        validate=None,
     ) -> DataFrame:
         from pandas.core.reshape.merge import merge
 

From 77e11425bd652bc7a3c108304ff5f487eab0ca58 Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Mon, 14 Dec 2020 14:02:24 -0500
Subject: [PATCH 10/21] minimize diff

---
 pandas/core/frame.py | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index f7d4bc4024614..b2376244fb446 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -8197,13 +8197,7 @@ def join(
         )
 
     def _join_compat(
-        self,
-        other,
-        on=None,
-        how="left",
-        lsuffix="",
-        rsuffix="",
-        sort=False,
+        self, other, on=None, how="left", lsuffix="", rsuffix="", sort=False
     ):
         from pandas.core.reshape.concat import concat
         from pandas.core.reshape.merge import merge

From 2352e454270a9cdf75c73b5e2857012b2cbc42b0 Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Mon, 14 Dec 2020 14:16:28 -0500
Subject: [PATCH 11/21] fix eval return type annotation

---
 pandas/core/frame.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index b2376244fb446..df67321d07907 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -3512,7 +3512,7 @@ def query(self, expr: str, inplace: bool = False, **kwargs) -> Optional[DataFram
 
     def eval(
         self, expr: str, inplace: bool = False, **kwargs
-    ) -> Optional[Union[AnyArrayLike, Scalar]]:
+    ) -> Optional[Union[AnyArrayLike, DataFrame, Scalar]]:
         """
         Evaluate a string describing operations on DataFrame columns.
 

From 1c942fd109f4a57173660ca671f8c7580f8e8e19 Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Mon, 14 Dec 2020 20:43:34 -0500
Subject: [PATCH 12/21] review comments

---
 pandas/core/frame.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 27d513a64023f..913fcf9c9e6f0 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -1457,7 +1457,7 @@ def to_numpy(
 
         return result
 
-    def to_dict(self, orient: str = "dict", into=dict) -> Union[Dict, List, Mapping]:
+    def to_dict(self, orient: str = "dict", into=dict) -> Union[List, Mapping]:
         """
         Convert the DataFrame to a dictionary.
 
@@ -3970,7 +3970,7 @@ def _sanitize_column(self, value):
         return value
 
     @property
-    def _series(self) -> "Dict[int, Series]":
+    def _series(self) -> Dict[int, Series]:
         return {
             item: Series(
                 self._mgr.iget(idx), index=self.index, name=item, fastpath=True

From 11247d9fc3354d7f8d1fbf516573fc851935fbbd Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Mon, 21 Dec 2020 13:41:15 -0500
Subject: [PATCH 13/21] review comments

---
 pandas/core/frame.py | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 913fcf9c9e6f0..cb6f883b75c02 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -3378,7 +3378,7 @@ def _box_col_values(self, values, loc: int) -> Series:
     # ----------------------------------------------------------------------
     # Unsorted
 
-    def query(self, expr: str, inplace: bool = False, **kwargs) -> Optional[DataFrame]:
+    def query(self, expr: str, inplace: bool = False, **kwargs):
         """
         Query the columns of a DataFrame with a boolean expression.
 
@@ -3543,9 +3543,7 @@ def query(self, expr: str, inplace: bool = False, **kwargs) -> Optional[DataFram
         else:
             return result
 
-    def eval(
-        self, expr: str, inplace: bool = False, **kwargs
-    ) -> Optional[Union[AnyArrayLike, DataFrame, Scalar]]:
+    def eval(self, expr: str, inplace: bool = False, **kwargs):
         """
         Evaluate a string describing operations on DataFrame columns.
 
@@ -6119,7 +6117,7 @@ def _arith_op(left, right):
         new_data = self._dispatch_frame_op(other, _arith_op)
         return new_data
 
-    def _construct_result(self, result: DataFrame) -> DataFrame:
+    def _construct_result(self, result):
         """
         Wrap the result of an arithmetic, comparison, or logical operation.
 

From 168cad26dbee00fb9670b8e9304d6c826378097a Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Mon, 4 Jan 2021 19:00:33 -0500
Subject: [PATCH 14/21] review comments

---
 pandas/core/frame.py | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 94b56036bc67d..8cd15fbd5c9be 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -50,7 +50,6 @@
 from pandas._libs.lib import no_default
 from pandas._typing import (
     AggFuncType,
-    AnyArrayLike,
     ArrayLike,
     Axes,
     Axis,
@@ -1073,7 +1072,7 @@ def iterrows(self) -> Iterable[Tuple[Label, Series]]:
 
     def itertuples(
         self, index: bool = True, name: Optional[str] = "Pandas"
-    ) -> Iterable[Tuple]:
+    ) -> Iterable[Tuple[Any, ...]]:
         """
         Iterate over DataFrame rows as namedtuples.
 
@@ -1163,7 +1162,7 @@ def __len__(self) -> int:
         """
         return len(self.index)
 
-    def dot(self, other: Union[AnyArrayLike, FrameOrSeriesUnion]) -> FrameOrSeriesUnion:
+    def dot(self, other):
         """
         Compute the matrix multiplication between the DataFrame and other.
 
@@ -1273,17 +1272,13 @@ def dot(self, other: Union[AnyArrayLike, FrameOrSeriesUnion]) -> FrameOrSeriesUn
         else:  # pragma: no cover
             raise TypeError(f"unsupported type: {type(other)}")
 
-    def __matmul__(
-        self, other: Union[AnyArrayLike, FrameOrSeriesUnion]
-    ) -> FrameOrSeriesUnion:
+    def __matmul__(self, other):
         """
         Matrix multiplication using binary `@` operator in Python>=3.5.
         """
         return self.dot(other)
 
-    def __rmatmul__(
-        self, other: Union[AnyArrayLike, FrameOrSeriesUnion]
-    ) -> FrameOrSeriesUnion:
+    def __rmatmul__(self, other):
         """
         Matrix multiplication using binary `@` operator in Python>=3.5.
         """

From 6c876ffa2ba41da95f4f38df6a80cbaa7aaae3a8 Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Mon, 4 Jan 2021 19:27:02 -0500
Subject: [PATCH 15/21] review comments

---
 pandas/core/frame.py | 37 ++++++++++++++++++++++++-------------
 1 file changed, 24 insertions(+), 13 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 9fe256a377a59..f6636104c9af8 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -64,6 +64,7 @@
     IndexLabel,
     Label,
     Level,
+    NpDtype,
     PythonFuncType,
     Renamer,
     Scalar,
@@ -1365,7 +1366,7 @@ def from_dict(
 
     def to_numpy(
         self,
-        dtype: Optional[Dtype] = None,
+        dtype: Optional[NpDtype] = None,
         copy: bool = False,
         na_value: Scalar = lib.no_default,
     ) -> np.ndarray:
@@ -1723,7 +1724,7 @@ def from_records(
         exclude=None,
         columns=None,
         coerce_float: bool = False,
-        nrows: Optional[bool] = None,
+        nrows: Optional[int] = None,
     ) -> DataFrame:
         """
         Convert structured or record ndarray to DataFrame.
@@ -2706,7 +2707,7 @@ def info(
             show_counts=show_counts,
         )
 
-    def memory_usage(self, index: bool = True, deep: bool = False) -> Series:
+    def memory_usage(self, index: bool = True, deep: bool = False):
         """
         Return the memory usage of each column in bytes.
 
@@ -2929,7 +2930,7 @@ def T(self) -> DataFrame:
     # ----------------------------------------------------------------------
     # Indexing Methods
 
-    def _ixs(self, i: int, axis: Axis = 0):
+    def _ixs(self, i: int, axis: int = 0):
         """
         Parameters
         ----------
@@ -3286,17 +3287,20 @@ def _set_item(self, key, value) -> None:
         self._set_item_mgr(key, value)
 
     def _set_value(
-        self, index: int, col, value: Scalar, takeable: bool = False
+        self, index: Label, col, value: Scalar, takeable: bool = False
     ) -> None:
         """
         Put single value at passed column and index.
 
         Parameters
         ----------
-        index : row label
-        col : column label
+        index : Label
+            row label
+        col : Label
+            column label
         value : scalar
-        takeable : interpret the index/col as indexers, default False
+        takeable : bool, default False
+            Sets whether or not index/col interpreted as indexers
         """
         try:
             if takeable is True:
@@ -3945,7 +3949,7 @@ def _sanitize_column(self, value):
         return value
 
     @property
-    def _series(self) -> Dict[int, Series]:
+    def _series(self) -> Dict[Label, Series]:
         return {
             item: Series(
                 self._mgr.iget(idx), index=self.index, name=item, fastpath=True
@@ -6097,7 +6101,7 @@ def _arith_op(left, right):
         new_data = self._dispatch_frame_op(other, _arith_op)
         return new_data
 
-    def _construct_result(self, result):
+    def _construct_result(self, result) -> DataFrame:
         """
         Wrap the result of an arithmetic, comparison, or logical operation.
 
@@ -8284,7 +8288,7 @@ def merge(
         )
 
     def round(
-        self, decimals: Union[int, Dict, Series] = 0, *args, **kwargs
+        self, decimals: Union[int, Dict[Label, int], Series] = 0, *args, **kwargs
     ) -> DataFrame:
         """
         Round a DataFrame to a variable number of decimal places.
@@ -8400,7 +8404,9 @@ def _series_round(s, decimals):
     # Statistical methods, etc.
 
     def corr(
-        self, method: Union[str, Callable] = "pearson", min_periods: int = 1
+        self,
+        method: Union[str, Callable[[np.ndarray, np.ndarray], float]] = "pearson",
+        min_periods: int = 1,
     ) -> DataFrame:
         """
         Compute pairwise correlation of columns, excluding NA/null values.
@@ -9489,7 +9495,12 @@ def to_period(
         setattr(new_obj, axis_name, new_ax)
         return new_obj
 
-    def isin(self, values: Union[FrameOrSeriesUnion, Dict, Iterable]) -> DataFrame:
+    def isin(
+        self,
+        values: Union[
+            FrameOrSeriesUnion, Dict[Label, Iterable[Scalar]], Iterable[Scalar]
+        ],
+    ) -> DataFrame:
         """
         Whether each element in the DataFrame is contained in values.
 

From 0e780ce0b8f474e2cae8630567f5f4cac6c730f5 Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Mon, 4 Jan 2021 20:06:27 -0500
Subject: [PATCH 16/21] review comments

---
 pandas/_typing.py    |  1 +
 pandas/core/frame.py | 20 +++++++++++---------
 2 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/pandas/_typing.py b/pandas/_typing.py
index 0b50dd69f7abb..8f3ef93e27bb0 100644
--- a/pandas/_typing.py
+++ b/pandas/_typing.py
@@ -84,6 +84,7 @@
 FrameOrSeries = TypeVar("FrameOrSeries", bound="NDFrame")
 
 Axis = Union[str, int]
+Frequency = Optional[str]
 Label = Optional[Hashable]
 IndexLabel = Union[Label, Sequence[Label]]
 Level = Union[Label, int]
diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index f6636104c9af8..63caf4efce5d8 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -29,7 +29,6 @@
     Iterable,
     Iterator,
     List,
-    Mapping,
     Optional,
     Sequence,
     Set,
@@ -60,6 +59,7 @@
     FloatFormatType,
     FormattersType,
     FrameOrSeriesUnion,
+    Frequency,
     IndexKeyFunc,
     IndexLabel,
     Label,
@@ -1435,7 +1435,7 @@ def to_numpy(
 
         return result
 
-    def to_dict(self, orient: str = "dict", into=dict) -> Union[List, Mapping]:
+    def to_dict(self, orient: str = "dict", into=dict):
         """
         Convert the DataFrame to a dictionary.
 
@@ -4581,7 +4581,11 @@ def _replace_columnwise(
 
     @doc(NDFrame.shift, klass=_shared_doc_kwargs["klass"])
     def shift(
-        self, periods=1, freq=None, axis: Axis = 0, fill_value=lib.no_default
+        self,
+        periods=1,
+        freq: Frequency = None,
+        axis: Axis = 0,
+        fill_value=lib.no_default,
     ) -> DataFrame:
         axis = self._get_axis_number(axis)
 
@@ -9378,7 +9382,7 @@ def quantile(
     @doc(NDFrame.asfreq, **_shared_doc_kwargs)
     def asfreq(
         self,
-        freq,
+        freq: Frequency,
         method=None,
         how: Optional[str] = None,
         normalize: bool = False,
@@ -9425,7 +9429,7 @@ def resample(
 
     def to_timestamp(
         self,
-        freq: Optional[str] = None,
+        freq: Frequency = None,
         how: str = "start",
         axis: Axis = 0,
         copy: bool = True,
@@ -9462,7 +9466,7 @@ def to_timestamp(
         return new_obj
 
     def to_period(
-        self, freq: Optional[str] = None, axis: Axis = 0, copy: bool = True
+        self, freq: Frequency = None, axis: Axis = 0, copy: bool = True
     ) -> DataFrame:
         """
         Convert DataFrame from DatetimeIndex to PeriodIndex.
@@ -9497,9 +9501,7 @@ def to_period(
 
     def isin(
         self,
-        values: Union[
-            FrameOrSeriesUnion, Dict[Label, Iterable[Scalar]], Iterable[Scalar]
-        ],
+        values,
     ) -> DataFrame:
         """
         Whether each element in the DataFrame is contained in values.

From a93489a4e71c87c5c3679d3da69a3adfe033c6ec Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Wed, 6 Jan 2021 08:35:14 -0500
Subject: [PATCH 17/21] review: remove NpDtype usage

---
 pandas/core/frame.py | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 63caf4efce5d8..6efb1a4e3e257 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -64,7 +64,6 @@
     IndexLabel,
     Label,
     Level,
-    NpDtype,
     PythonFuncType,
     Renamer,
     Scalar,
@@ -1366,7 +1365,7 @@ def from_dict(
 
     def to_numpy(
         self,
-        dtype: Optional[NpDtype] = None,
+        dtype=None,
         copy: bool = False,
         na_value: Scalar = lib.no_default,
     ) -> np.ndarray:

From 58fcad886ab24e99ce66079a67fbc8e9dc3c73cd Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Sun, 21 Feb 2021 14:29:08 -0500
Subject: [PATCH 18/21] typing

---
 pandas/core/frame.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 35ff01202fdfb..c8e86fc8fc591 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -1373,7 +1373,7 @@ def from_dict(
         data,
         orient: str = "columns",
         dtype: Optional[Dtype] = None,
-        columns: Optional[IndexLabel] = None,
+        columns=None,
     ) -> DataFrame:
         """
         Construct DataFrame from dict of array-like or dicts.
@@ -4072,7 +4072,7 @@ def _series(self) -> Dict[IndexLabel, Series]:
         }
 
     def lookup(
-        self, row_labels: Sequence[IndexLabel], col_labels: IndexLabel
+        self, row_labels: Sequence[IndexLabel], col_labels: Sequence[IndexLabel]
     ) -> np.ndarray:
         """
         Label-based "fancy indexing" function for DataFrame.

From ff317d35ce096f4841afc38a1b62c1b4d44ae45c Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Mon, 22 Feb 2021 11:15:36 -0500
Subject: [PATCH 19/21] restore return type for memory_usage

---
 pandas/core/frame.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index c8e86fc8fc591..8f0411e6d44d0 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -2794,7 +2794,7 @@ def info(
             show_counts=show_counts,
         )
 
-    def memory_usage(self, index: bool = True, deep: bool = False):
+    def memory_usage(self, index: bool = True, deep: bool = False) -> Series:
         """
         Return the memory usage of each column in bytes.
 

From 02647b528234963d89412c0fa26944e70144089e Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Mon, 22 Feb 2021 11:16:40 -0500
Subject: [PATCH 20/21] remove return type for _series

---
 pandas/core/frame.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 8f0411e6d44d0..03e429e4cbe1a 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -4063,7 +4063,7 @@ def _sanitize_column(self, value):
         return value
 
     @property
-    def _series(self) -> Dict[IndexLabel, Series]:
+    def _series(self):
         return {
             item: Series(
                 self._mgr.iget(idx), index=self.index, name=item, fastpath=True

From cc517a518e2b2e97fc719fe20105663ee222a1ad Mon Sep 17 00:00:00 2001
From: Andrew Wieteska <andrew.r.wieteska@gmail.com>
Date: Mon, 22 Feb 2021 11:17:44 -0500
Subject: [PATCH 21/21] rogue comma

---
 pandas/core/frame.py | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/pandas/core/frame.py b/pandas/core/frame.py
index 03e429e4cbe1a..8934438e3281a 100644
--- a/pandas/core/frame.py
+++ b/pandas/core/frame.py
@@ -9620,10 +9620,7 @@ def to_period(
         setattr(new_obj, axis_name, new_ax)
         return new_obj
 
-    def isin(
-        self,
-        values,
-    ) -> DataFrame:
+    def isin(self, values) -> DataFrame:
         """
         Whether each element in the DataFrame is contained in values.