From 648e005d3eb16a51b9c6108dc8c78d7140f589ac Mon Sep 17 00:00:00 2001
From: Joris Van den Bossche <jorisvandenbossche@gmail.com>
Date: Mon, 1 Mar 2021 12:23:36 +0100
Subject: [PATCH 1/5] REF: move Block.astype implementation to array_algos

---
 pandas/core/array_algos/cast.py           | 118 ++++++++++++++++++++++
 pandas/core/internals/array_manager.py    |   3 +-
 pandas/core/internals/blocks.py           |  66 +-----------
 pandas/tests/frame/methods/test_astype.py |   8 --
 pandas/util/_exceptions.py                |   2 +-
 5 files changed, 126 insertions(+), 71 deletions(-)
 create mode 100644 pandas/core/array_algos/cast.py

diff --git a/pandas/core/array_algos/cast.py b/pandas/core/array_algos/cast.py
new file mode 100644
index 0000000000000..80d8caa4bc328
--- /dev/null
+++ b/pandas/core/array_algos/cast.py
@@ -0,0 +1,118 @@
+import inspect
+
+import numpy as np
+
+from pandas._typing import (
+    ArrayLike,
+    Dtype,
+    DtypeObj,
+)
+
+from pandas.core.dtypes.cast import (
+    astype_dt64_to_dt64tz,
+    astype_nansafe,
+)
+from pandas.core.dtypes.common import (
+    is_datetime64_dtype,
+    is_datetime64tz_dtype,
+    is_dtype_equal,
+    pandas_dtype,
+)
+from pandas.core.dtypes.dtypes import ExtensionDtype
+
+from pandas.core.arrays import ExtensionArray
+
+
+def astype_array(values: ArrayLike, dtype: DtypeObj, copy: bool = False):
+    """
+    Cast array to the new dtype.
+
+    Parameters
+    ----------
+    values : ndarray or ExtensionArray
+    dtype : str, dtype convertible
+    copy : bool, default False
+        copy if indicated
+
+    Returns
+    -------
+    ndarray or ExtensionArray
+    """
+    if (
+        values.dtype.kind in ["m", "M"]
+        and dtype.kind in ["i", "u"]
+        and isinstance(dtype, np.dtype)
+        and dtype.itemsize != 8
+    ):
+        # TODO(2.0) remove special case once deprecation on DTA/TDA is enforced
+        msg = rf"cannot astype a datetimelike from [{values.dtype}] to [{dtype}]"
+        raise TypeError(msg)
+
+    if is_datetime64tz_dtype(dtype) and is_datetime64_dtype(values.dtype):
+        return astype_dt64_to_dt64tz(values, dtype, copy, via_utc=True)
+
+    if is_dtype_equal(values.dtype, dtype):
+        if copy:
+            return values.copy()
+        return values
+
+    if isinstance(values, ExtensionArray):
+        values = values.astype(dtype, copy=copy)
+
+    else:
+        values = astype_nansafe(values, dtype, copy=copy)
+
+    # now in ObjectBlock._maybe_coerce_values(cls, values):
+    if isinstance(dtype, np.dtype) and issubclass(values.dtype.type, str):
+        values = np.array(values, dtype=object)
+
+    return values
+
+
+def astype_array_safe(values, dtype: Dtype, copy: bool = False, errors: str = "raise"):
+    """
+    Cast array to the new dtype.
+
+    Parameters
+    ----------
+    values : ndarray or ExtensionArray
+    dtype : str, dtype convertible
+    copy : bool, default False
+        copy if indicated
+    errors : str, {'raise', 'ignore'}, default 'raise'
+        - ``raise`` : allow exceptions to be raised
+        - ``ignore`` : suppress exceptions. On error return original object
+
+    Returns
+    -------
+    ndarray or ExtensionArray
+    """
+    errors_legal_values = ("raise", "ignore")
+
+    if errors not in errors_legal_values:
+        invalid_arg = (
+            "Expected value of kwarg 'errors' to be one of "
+            f"{list(errors_legal_values)}. Supplied value is '{errors}'"
+        )
+        raise ValueError(invalid_arg)
+
+    if inspect.isclass(dtype) and issubclass(dtype, ExtensionDtype):
+        msg = (
+            f"Expected an instance of {dtype.__name__}, "
+            "but got the class instead. Try instantiating 'dtype'."
+        )
+        raise TypeError(msg)
+
+    dtype = pandas_dtype(dtype)
+
+    try:
+        new_values = astype_array(values, dtype, copy=copy)
+    except (ValueError, TypeError):
+        # e.g. astype_nansafe can fail on object-dtype of strings
+        #  trying to convert to float
+        if errors == "ignore":
+            new_values = values
+        else:
+            raise
+
+    return new_values
diff --git a/pandas/core/internals/array_manager.py b/pandas/core/internals/array_manager.py
index 5001754017dda..f7b7ed47409c7 100644
--- a/pandas/core/internals/array_manager.py
+++ b/pandas/core/internals/array_manager.py
@@ -53,6 +53,7 @@
 )
 
 import pandas.core.algorithms as algos
+from pandas.core.array_algos.cast import astype_array_safe
 from pandas.core.arrays import ExtensionArray
 from pandas.core.arrays.sparse import SparseDtype
 from pandas.core.construction import (
@@ -499,7 +500,7 @@ def downcast(self) -> ArrayManager:
         return self.apply_with_block("downcast")
 
     def astype(self, dtype, copy: bool = False, errors: str = "raise") -> ArrayManager:
-        return self.apply("astype", dtype=dtype, copy=copy)  # , errors=errors)
+        return self.apply(astype_array_safe, dtype=dtype, copy=copy, errors=errors)
 
     def convert(
         self,
diff --git a/pandas/core/internals/blocks.py b/pandas/core/internals/blocks.py
index b65043be6fda6..1d61c647a36fb 100644
--- a/pandas/core/internals/blocks.py
+++ b/pandas/core/internals/blocks.py
@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import inspect
 import re
 from typing import (
     TYPE_CHECKING,
@@ -36,8 +35,6 @@
 from pandas.util._validators import validate_bool_kwarg
 
 from pandas.core.dtypes.cast import (
-    astype_dt64_to_dt64tz,
-    astype_nansafe,
     can_hold_element,
     find_common_type,
     infer_dtype_from,
@@ -49,7 +46,6 @@
 )
 from pandas.core.dtypes.common import (
     is_categorical_dtype,
-    is_datetime64_dtype,
     is_datetime64tz_dtype,
     is_dtype_equal,
     is_extension_array_dtype,
@@ -76,6 +72,7 @@
 )
 
 import pandas.core.algorithms as algos
+from pandas.core.array_algos.cast import astype_array_safe
 from pandas.core.array_algos.putmask import (
     extract_bool_array,
     putmask_inplace,
@@ -652,33 +649,11 @@ def astype(self, dtype, copy: bool = False, errors: str = "raise"):
         -------
         Block
         """
-        errors_legal_values = ("raise", "ignore")
-
-        if errors not in errors_legal_values:
-            invalid_arg = (
-                "Expected value of kwarg 'errors' to be one of "
-                f"{list(errors_legal_values)}. Supplied value is '{errors}'"
-            )
-            raise ValueError(invalid_arg)
-
-        if inspect.isclass(dtype) and issubclass(dtype, ExtensionDtype):
-            msg = (
-                f"Expected an instance of {dtype.__name__}, "
-                "but got the class instead. Try instantiating 'dtype'."
-            )
-            raise TypeError(msg)
-
-        dtype = pandas_dtype(dtype)
+        values = self.values
+        if values.dtype.kind in ["m", "M"]:
+            values = self.array_values()
 
-        try:
-            new_values = self._astype(dtype, copy=copy)
-        except (ValueError, TypeError):
-            # e.g. astype_nansafe can fail on object-dtype of strings
-            #  trying to convert to float
-            if errors == "ignore":
-                new_values = self.values
-            else:
-                raise
+        new_values = astype_array_safe(values, dtype, copy=copy, errors=errors)
 
         newb = self.make_block(new_values)
         if newb.shape != self.shape:
@@ -689,37 +664,6 @@ def astype(self, dtype, copy: bool = False, errors: str = "raise"):
             )
         return newb
 
-    def _astype(self, dtype: DtypeObj, copy: bool) -> ArrayLike:
-        values = self.values
-        if values.dtype.kind in ["m", "M"]:
-            values = self.array_values()
-
-        if (
-            values.dtype.kind in ["m", "M"]
-            and dtype.kind in ["i", "u"]
-            and isinstance(dtype, np.dtype)
-            and dtype.itemsize != 8
-        ):
-            # TODO(2.0) remove special case once deprecation on DTA/TDA is enforced
-            msg = rf"cannot astype a datetimelike from [{values.dtype}] to [{dtype}]"
-            raise TypeError(msg)
-
-        if is_datetime64tz_dtype(dtype) and is_datetime64_dtype(values.dtype):
-            return astype_dt64_to_dt64tz(values, dtype, copy, via_utc=True)
-
-        if is_dtype_equal(values.dtype, dtype):
-            if copy:
-                return values.copy()
-            return values
-
-        if isinstance(values, ExtensionArray):
-            values = values.astype(dtype, copy=copy)
-
-        else:
-            values = astype_nansafe(values, dtype, copy=copy)
-
-        return values
-
     def convert(
         self,
         copy: bool = True,
diff --git a/pandas/tests/frame/methods/test_astype.py b/pandas/tests/frame/methods/test_astype.py
index 8c11f659e8454..161fe7990a327 100644
--- a/pandas/tests/frame/methods/test_astype.py
+++ b/pandas/tests/frame/methods/test_astype.py
@@ -3,8 +3,6 @@
 import numpy as np
 import pytest
 
-import pandas.util._test_decorators as td
-
 import pandas as pd
 from pandas import (
     Categorical,
@@ -92,7 +90,6 @@ def test_astype_mixed_type(self, mixed_type_frame):
         casted = mn.astype("O")
         _check_cast(casted, "object")
 
-    @td.skip_array_manager_not_yet_implemented
     def test_astype_with_exclude_string(self, float_frame):
         df = float_frame.copy()
         expected = float_frame.astype(int)
@@ -127,7 +124,6 @@ def test_astype_with_view_mixed_float(self, mixed_float_frame):
         casted = tf.astype(np.int64)
         casted = tf.astype(np.float32)  # noqa
 
-    @td.skip_array_manager_not_yet_implemented
     @pytest.mark.parametrize("dtype", [np.int32, np.int64])
     @pytest.mark.parametrize("val", [np.nan, np.inf])
     def test_astype_cast_nan_inf_int(self, val, dtype):
@@ -386,7 +382,6 @@ def test_astype_to_datetimelike_unit(self, arr_dtype, dtype, unit):
 
         tm.assert_frame_equal(result, expected)
 
-    @td.skip_array_manager_not_yet_implemented
     @pytest.mark.parametrize("unit", ["ns", "us", "ms", "s", "h", "m", "D"])
     def test_astype_to_datetime_unit(self, unit):
         # tests all units from datetime origination
@@ -411,7 +406,6 @@ def test_astype_to_timedelta_unit_ns(self, unit):
 
         tm.assert_frame_equal(result, expected)
 
-    @td.skip_array_manager_not_yet_implemented
     @pytest.mark.parametrize("unit", ["us", "ms", "s", "h", "m", "D"])
     def test_astype_to_timedelta_unit(self, unit):
         # coerce to float
@@ -441,7 +435,6 @@ def test_astype_to_incorrect_datetimelike(self, unit):
         with pytest.raises(TypeError, match=msg):
             df.astype(dtype)
 
-    @td.skip_array_manager_not_yet_implemented
     def test_astype_arg_for_errors(self):
         # GH#14878
 
@@ -570,7 +563,6 @@ def test_astype_empty_dtype_dict(self):
         tm.assert_frame_equal(result, df)
         assert result is not df
 
-    @td.skip_array_manager_not_yet_implemented  # TODO(ArrayManager) ignore keyword
     @pytest.mark.parametrize(
         "df",
         [
diff --git a/pandas/util/_exceptions.py b/pandas/util/_exceptions.py
index 5ca96a1f9989f..c31c421ee1445 100644
--- a/pandas/util/_exceptions.py
+++ b/pandas/util/_exceptions.py
@@ -31,7 +31,7 @@ def find_stack_level() -> int:
         if stack[n].function == "astype":
             break
 
-    while stack[n].function in ["astype", "apply", "_astype"]:
+    while stack[n].function in ["astype", "apply", "astype_array_safe", "astype_array"]:
         # e.g.
         #  bump up Block.astype -> BlockManager.astype -> NDFrame.astype
         #  bump up Datetime.Array.astype -> DatetimeIndex.astype

From 2f52197aacfc46f30deda6179d598ac4574ce4bc Mon Sep 17 00:00:00 2001
From: Joris Van den Bossche <jorisvandenbossche@gmail.com>
Date: Mon, 1 Mar 2021 13:22:08 +0100
Subject: [PATCH 2/5] update docstring

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

diff --git a/pandas/core/array_algos/cast.py b/pandas/core/array_algos/cast.py
index 80d8caa4bc328..396d015460839 100644
--- a/pandas/core/array_algos/cast.py
+++ b/pandas/core/array_algos/cast.py
@@ -30,7 +30,7 @@ def astype_array(values: ArrayLike, dtype: DtypeObj, copy: bool = False):
     Parameters
     ----------
     values : ndarray or ExtensionArray
-    dtype : str, dtype convertible
+    dtype : dtype object
     copy : bool, default False
         copy if indicated
 

From aefc4623bc68f725663f24b4666ee81dae079111 Mon Sep 17 00:00:00 2001
From: Joris Van den Bossche <jorisvandenbossche@gmail.com>
Date: Mon, 1 Mar 2021 13:27:17 +0100
Subject: [PATCH 3/5] fix mypy

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

diff --git a/pandas/core/array_algos/cast.py b/pandas/core/array_algos/cast.py
index 396d015460839..4a5cc0a406815 100644
--- a/pandas/core/array_algos/cast.py
+++ b/pandas/core/array_algos/cast.py
@@ -4,7 +4,6 @@
 
 from pandas._typing import (
     ArrayLike,
-    Dtype,
     DtypeObj,
 )
 
@@ -69,7 +68,7 @@ def astype_array(values: ArrayLike, dtype: DtypeObj, copy: bool = False):
     return values
 
 
-def astype_array_safe(values, dtype: Dtype, copy: bool = False, errors: str = "raise"):
+def astype_array_safe(values, dtype, copy: bool = False, errors: str = "raise"):
     """
     Cast array to the new dtype.
 

From 01941b788dccb9c99e5a276c99058eab58ec3cb0 Mon Sep 17 00:00:00 2001
From: Joris Van den Bossche <jorisvandenbossche@gmail.com>
Date: Mon, 1 Mar 2021 19:15:40 +0100
Subject: [PATCH 4/5] move to core/dtypes/cast.py

---
 pandas/core/array_algos/cast.py        | 117 -------------------------
 pandas/core/dtypes/cast.py             | 103 ++++++++++++++++++++++
 pandas/core/internals/array_manager.py |   2 +-
 pandas/core/internals/blocks.py        |   2 +-
 4 files changed, 105 insertions(+), 119 deletions(-)
 delete mode 100644 pandas/core/array_algos/cast.py

diff --git a/pandas/core/array_algos/cast.py b/pandas/core/array_algos/cast.py
deleted file mode 100644
index 4a5cc0a406815..0000000000000
--- a/pandas/core/array_algos/cast.py
+++ /dev/null
@@ -1,117 +0,0 @@
-import inspect
-
-import numpy as np
-
-from pandas._typing import (
-    ArrayLike,
-    DtypeObj,
-)
-
-from pandas.core.dtypes.cast import (
-    astype_dt64_to_dt64tz,
-    astype_nansafe,
-)
-from pandas.core.dtypes.common import (
-    is_datetime64_dtype,
-    is_datetime64tz_dtype,
-    is_dtype_equal,
-    pandas_dtype,
-)
-from pandas.core.dtypes.dtypes import ExtensionDtype
-
-from pandas.core.arrays import ExtensionArray
-
-
-def astype_array(values: ArrayLike, dtype: DtypeObj, copy: bool = False):
-    """
-    Cast array to the new dtype.
-
-    Parameters
-    ----------
-    values : ndarray or ExtensionArray
-    dtype : dtype object
-    copy : bool, default False
-        copy if indicated
-
-    Returns
-    -------
-    ndarray or ExtensionArray
-    """
-    if (
-        values.dtype.kind in ["m", "M"]
-        and dtype.kind in ["i", "u"]
-        and isinstance(dtype, np.dtype)
-        and dtype.itemsize != 8
-    ):
-        # TODO(2.0) remove special case once deprecation on DTA/TDA is enforced
-        msg = rf"cannot astype a datetimelike from [{values.dtype}] to [{dtype}]"
-        raise TypeError(msg)
-
-    if is_datetime64tz_dtype(dtype) and is_datetime64_dtype(values.dtype):
-        return astype_dt64_to_dt64tz(values, dtype, copy, via_utc=True)
-
-    if is_dtype_equal(values.dtype, dtype):
-        if copy:
-            return values.copy()
-        return values
-
-    if isinstance(values, ExtensionArray):
-        values = values.astype(dtype, copy=copy)
-
-    else:
-        values = astype_nansafe(values, dtype, copy=copy)
-
-    # now in ObjectBlock._maybe_coerce_values(cls, values):
-    if isinstance(dtype, np.dtype) and issubclass(values.dtype.type, str):
-        values = np.array(values, dtype=object)
-
-    return values
-
-
-def astype_array_safe(values, dtype, copy: bool = False, errors: str = "raise"):
-    """
-    Cast array to the new dtype.
-
-    Parameters
-    ----------
-    values : ndarray or ExtensionArray
-    dtype : str, dtype convertible
-    copy : bool, default False
-        copy if indicated
-    errors : str, {'raise', 'ignore'}, default 'raise'
-        - ``raise`` : allow exceptions to be raised
-        - ``ignore`` : suppress exceptions. On error return original object
-
-    Returns
-    -------
-    ndarray or ExtensionArray
-    """
-    errors_legal_values = ("raise", "ignore")
-
-    if errors not in errors_legal_values:
-        invalid_arg = (
-            "Expected value of kwarg 'errors' to be one of "
-            f"{list(errors_legal_values)}. Supplied value is '{errors}'"
-        )
-        raise ValueError(invalid_arg)
-
-    if inspect.isclass(dtype) and issubclass(dtype, ExtensionDtype):
-        msg = (
-            f"Expected an instance of {dtype.__name__}, "
-            "but got the class instead. Try instantiating 'dtype'."
-        )
-        raise TypeError(msg)
-
-    dtype = pandas_dtype(dtype)
-
-    try:
-        new_values = astype_array(values, dtype, copy=copy)
-    except (ValueError, TypeError):
-        # e.g. astype_nansafe can fail on object-dtype of strings
-        #  trying to convert to float
-        if errors == "ignore":
-            new_values = values
-        else:
-            raise
-
-    return new_values
diff --git a/pandas/core/dtypes/cast.py b/pandas/core/dtypes/cast.py
index a93bf0c9211e1..4fb3f2ff76934 100644
--- a/pandas/core/dtypes/cast.py
+++ b/pandas/core/dtypes/cast.py
@@ -10,6 +10,7 @@
     datetime,
     timedelta,
 )
+import inspect
 from typing import (
     TYPE_CHECKING,
     Any,
@@ -86,6 +87,7 @@
     is_timedelta64_dtype,
     is_timedelta64_ns_dtype,
     is_unsigned_integer_dtype,
+    pandas_dtype,
 )
 from pandas.core.dtypes.dtypes import (
     DatetimeTZDtype,
@@ -1225,6 +1227,107 @@ def astype_nansafe(
     return arr.astype(dtype, copy=copy)
 
 
+def astype_array(values: ArrayLike, dtype: DtypeObj, copy: bool = False):
+    """
+    Cast array (ndarray or ExtensionArray) to the new dtype.
+
+    Parameters
+    ----------
+    values : ndarray or ExtensionArray
+    dtype : dtype object
+    copy : bool, default False
+        copy if indicated
+
+    Returns
+    -------
+    ndarray or ExtensionArray
+    """
+    if (
+        values.dtype.kind in ["m", "M"]
+        and dtype.kind in ["i", "u"]
+        and isinstance(dtype, np.dtype)
+        and dtype.itemsize != 8
+    ):
+        # TODO(2.0) remove special case once deprecation on DTA/TDA is enforced
+        msg = rf"cannot astype a datetimelike from [{values.dtype}] to [{dtype}]"
+        raise TypeError(msg)
+
+    if is_datetime64tz_dtype(dtype) and is_datetime64_dtype(values.dtype):
+        return astype_dt64_to_dt64tz(values, dtype, copy, via_utc=True)
+
+    if is_dtype_equal(values.dtype, dtype):
+        if copy:
+            return values.copy()
+        return values
+
+    if isinstance(values, ABCExtensionArray):
+        values = values.astype(dtype, copy=copy)
+
+    else:
+        values = astype_nansafe(values, dtype, copy=copy)
+
+    # in pandas we don't store numpy str dtypes, so convert to object
+    if isinstance(dtype, np.dtype) and issubclass(values.dtype.type, str):
+        values = np.array(values, dtype=object)
+
+    return values
+
+
+def astype_array_safe(
+    values: ArrayLike, dtype, copy: bool = False, errors: str = "raise"
+):
+    """
+    Cast array (ndarray or ExtensionArray) to the new dtype.
+
+    This basically is the implementation for DataFrame/Series.astype and
+    includes all custom logic for pandas (NaN-safety, converting str to object,
+    not allowing )
+
+    Parameters
+    ----------
+    values : ndarray or ExtensionArray
+    dtype : str, dtype convertible
+    copy : bool, default False
+        copy if indicated
+    errors : str, {'raise', 'ignore'}, default 'raise'
+        - ``raise`` : allow exceptions to be raised
+        - ``ignore`` : suppress exceptions. On error return original object
+
+    Returns
+    -------
+    ndarray or ExtensionArray
+    """
+    errors_legal_values = ("raise", "ignore")
+
+    if errors not in errors_legal_values:
+        invalid_arg = (
+            "Expected value of kwarg 'errors' to be one of "
+            f"{list(errors_legal_values)}. Supplied value is '{errors}'"
+        )
+        raise ValueError(invalid_arg)
+
+    if inspect.isclass(dtype) and issubclass(dtype, ExtensionDtype):
+        msg = (
+            f"Expected an instance of {dtype.__name__}, "
+            "but got the class instead. Try instantiating 'dtype'."
+        )
+        raise TypeError(msg)
+
+    dtype = pandas_dtype(dtype)
+
+    try:
+        new_values = astype_array(values, dtype, copy=copy)
+    except (ValueError, TypeError):
+        # e.g. astype_nansafe can fail on object-dtype of strings
+        #  trying to convert to float
+        if errors == "ignore":
+            new_values = values
+        else:
+            raise
+
+    return new_values
+
+
 def soft_convert_objects(
     values: np.ndarray,
     datetime: bool = True,
diff --git a/pandas/core/internals/array_manager.py b/pandas/core/internals/array_manager.py
index f7b7ed47409c7..48e27e7100d2f 100644
--- a/pandas/core/internals/array_manager.py
+++ b/pandas/core/internals/array_manager.py
@@ -28,6 +28,7 @@
 from pandas.util._validators import validate_bool_kwarg
 
 from pandas.core.dtypes.cast import (
+    astype_array_safe,
     find_common_type,
     infer_dtype_from_scalar,
 )
@@ -53,7 +54,6 @@
 )
 
 import pandas.core.algorithms as algos
-from pandas.core.array_algos.cast import astype_array_safe
 from pandas.core.arrays import ExtensionArray
 from pandas.core.arrays.sparse import SparseDtype
 from pandas.core.construction import (
diff --git a/pandas/core/internals/blocks.py b/pandas/core/internals/blocks.py
index 1d61c647a36fb..f2b8499a316b7 100644
--- a/pandas/core/internals/blocks.py
+++ b/pandas/core/internals/blocks.py
@@ -35,6 +35,7 @@
 from pandas.util._validators import validate_bool_kwarg
 
 from pandas.core.dtypes.cast import (
+    astype_array_safe,
     can_hold_element,
     find_common_type,
     infer_dtype_from,
@@ -72,7 +73,6 @@
 )
 
 import pandas.core.algorithms as algos
-from pandas.core.array_algos.cast import astype_array_safe
 from pandas.core.array_algos.putmask import (
     extract_bool_array,
     putmask_inplace,

From 76d1e1cad64327e08d16f79a9e741a315c311a10 Mon Sep 17 00:00:00 2001
From: Joris Van den Bossche <jorisvandenbossche@gmail.com>
Date: Tue, 2 Mar 2021 16:56:02 +0100
Subject: [PATCH 5/5] add return type annotations

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

diff --git a/pandas/core/dtypes/cast.py b/pandas/core/dtypes/cast.py
index 4fb3f2ff76934..213c517c9db7c 100644
--- a/pandas/core/dtypes/cast.py
+++ b/pandas/core/dtypes/cast.py
@@ -1227,7 +1227,7 @@ def astype_nansafe(
     return arr.astype(dtype, copy=copy)
 
 
-def astype_array(values: ArrayLike, dtype: DtypeObj, copy: bool = False):
+def astype_array(values: ArrayLike, dtype: DtypeObj, copy: bool = False) -> ArrayLike:
     """
     Cast array (ndarray or ExtensionArray) to the new dtype.
 
@@ -1275,7 +1275,7 @@ def astype_array(values: ArrayLike, dtype: DtypeObj, copy: bool = False):
 
 def astype_array_safe(
     values: ArrayLike, dtype, copy: bool = False, errors: str = "raise"
-):
+) -> ArrayLike:
     """
     Cast array (ndarray or ExtensionArray) to the new dtype.