From f90bd922dd6e986badd0e8c22baa60ace9cab07f Mon Sep 17 00:00:00 2001
From: MarcoGorelli <33491632+MarcoGorelli@users.noreply.github.com>
Date: Thu, 5 Oct 2023 12:47:02 +0100
Subject: [PATCH 1/7] add datetime accessor

---
 .../dataframe_api/column_object.py            | 105 ++++++++++++++++++
 1 file changed, 105 insertions(+)

diff --git a/spec/API_specification/dataframe_api/column_object.py b/spec/API_specification/dataframe_api/column_object.py
index ff4d7ba3..81693cf0 100644
--- a/spec/API_specification/dataframe_api/column_object.py
+++ b/spec/API_specification/dataframe_api/column_object.py
@@ -2,6 +2,8 @@
 
 from typing import Any,NoReturn, TYPE_CHECKING, Literal, Generic
 
+from datetime import timedelta
+
 if TYPE_CHECKING:
     from ._types import NullType, Scalar, DType, Namespace
 
@@ -763,3 +765,106 @@ def rename(self, name: str) -> Column:
             New column - this does not operate in-place.
         """
         ...
+
+    @property
+    def dt(self) -> DatetimeAccessor:
+        """
+        Return accessor with functions which work on temporal dtypes.
+        """
+        ...
+
+class DatetimeAccessor:
+    """
+    Method which operate on temporal Columns.
+    """
+
+    def year(self) -> Column:
+        """
+        Return 'year' component of each element.
+        
+        For example, return 1981 for 1981-01-02T12:34:56.123456.
+        """
+
+    def month(self) -> Column:
+        """
+        Return 'month' component of each element.
+        
+        For example, return 1 for 1981-01-02T12:34:56.123456.
+        """
+
+    def day(self) -> Column:
+        """
+        Return 'day' component of each element.
+        
+        For example, return 2 for 1981-01-02T12:34:56.123456.
+        """
+
+    def hour(self) -> Column:
+        """
+        Return 'hour' component of each element.
+        
+        For example, return 12 for 1981-01-02T12:34:56.123456.
+        """
+
+    def minute(self) -> Column:
+        """
+        Return 'minute' component of each element.
+        
+        For example, return 34 for 1981-01-02T12:34:56.123456.
+        """
+
+    def second(self) -> Column:
+        """
+        Return 'second' component of each element.
+        
+        For example, return 56 for 1981-01-02T12:34:56.123456.
+        """
+
+    def microsecond(self) -> Column:
+        """
+        Return number of microseconds since last second, for each element.
+
+        For example, return 123456 for 1981-01-02T12:34:56.123456.
+        """
+    
+    def floor(self, frequency: timedelta) -> Column:
+        """
+        Return floor of each element according to the specified frequency.
+
+        Flooring is done according to local time. For example,
+        for a ``Datetime('us', 'Europe/London')`` column,
+        ``"2020-10-25T00:30:00 BST"`` floored by ``"1day"`` gives
+        ``"2020-10-25T00:00:00 BST"``.
+
+        Behaviours in the face of ambiguous and non-existent times are
+        currently unspecified and may vary across implementations.
+
+        Flooring by non-fixed durations (e.g. calendar month) are not supported.
+        Note that flooring by ``timedelta(days=1)`` is equivalent to flooring
+        by ``timedelta(hours=24)``.
+
+        Parameters
+        ----------
+        freq : timedelta
+            Frequency to floor by.
+        """
+
+    def iso_weekday(self) -> Column:
+        """
+        Return ISO weekday for each element.
+
+        Note that Monday=1, ..., Sunday=7.
+        """
+
+    def timestamp(self) -> Column:
+        """
+        Return number of units since UNIX epoch (1970-01-01).
+
+        Units depend on the dtype of the column:
+
+        - For a :class:`Date` column, ``1970-01-02`` should return `1`;
+        - For a :class:`Datetime('ms', '*')` column, ``1970-01-02``
+          should return `86_400_000`;
+        - For a :class:`Datetime('us', '*')` column, ``1970-01-02``
+          should return `86_400_000_000`;
+        """

From b7ffcaca20076b1fd954400a363c05b7db02ee5c Mon Sep 17 00:00:00 2001
From: MarcoGorelli <33491632+MarcoGorelli@users.noreply.github.com>
Date: Sat, 7 Oct 2023 13:05:22 +0300
Subject: [PATCH 2/7] remove floor

---
 .../dataframe_api/column_object.py            | 34 -------------------
 1 file changed, 34 deletions(-)

diff --git a/spec/API_specification/dataframe_api/column_object.py b/spec/API_specification/dataframe_api/column_object.py
index 81693cf0..98f58410 100644
--- a/spec/API_specification/dataframe_api/column_object.py
+++ b/spec/API_specification/dataframe_api/column_object.py
@@ -827,28 +827,6 @@ def microsecond(self) -> Column:
         For example, return 123456 for 1981-01-02T12:34:56.123456.
         """
     
-    def floor(self, frequency: timedelta) -> Column:
-        """
-        Return floor of each element according to the specified frequency.
-
-        Flooring is done according to local time. For example,
-        for a ``Datetime('us', 'Europe/London')`` column,
-        ``"2020-10-25T00:30:00 BST"`` floored by ``"1day"`` gives
-        ``"2020-10-25T00:00:00 BST"``.
-
-        Behaviours in the face of ambiguous and non-existent times are
-        currently unspecified and may vary across implementations.
-
-        Flooring by non-fixed durations (e.g. calendar month) are not supported.
-        Note that flooring by ``timedelta(days=1)`` is equivalent to flooring
-        by ``timedelta(hours=24)``.
-
-        Parameters
-        ----------
-        freq : timedelta
-            Frequency to floor by.
-        """
-
     def iso_weekday(self) -> Column:
         """
         Return ISO weekday for each element.
@@ -856,15 +834,3 @@ def iso_weekday(self) -> Column:
         Note that Monday=1, ..., Sunday=7.
         """
 
-    def timestamp(self) -> Column:
-        """
-        Return number of units since UNIX epoch (1970-01-01).
-
-        Units depend on the dtype of the column:
-
-        - For a :class:`Date` column, ``1970-01-02`` should return `1`;
-        - For a :class:`Datetime('ms', '*')` column, ``1970-01-02``
-          should return `86_400_000`;
-        - For a :class:`Datetime('us', '*')` column, ``1970-01-02``
-          should return `86_400_000_000`;
-        """

From 41017d9d4b52e1b9eeacd5d608f23076f9c2bb14 Mon Sep 17 00:00:00 2001
From: MarcoGorelli <33491632+MarcoGorelli@users.noreply.github.com>
Date: Sat, 7 Oct 2023 13:46:24 +0300
Subject: [PATCH 3/7] fixup

---
 spec/API_specification/column_object.rst              | 2 ++
 spec/API_specification/dataframe_api/__init__.py      | 1 +
 spec/API_specification/dataframe_api/column_object.py | 4 ++--
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/spec/API_specification/column_object.rst b/spec/API_specification/column_object.rst
index 3201b500..5ff16633 100644
--- a/spec/API_specification/column_object.rst
+++ b/spec/API_specification/column_object.rst
@@ -10,3 +10,5 @@ behavior.
 .. currentmodule:: dataframe_api
 
 .. autoclass:: Column
+
+.. autoclass:: DatetimeAccessor
diff --git a/spec/API_specification/dataframe_api/__init__.py b/spec/API_specification/dataframe_api/__init__.py
index 4829eb48..a4218650 100644
--- a/spec/API_specification/dataframe_api/__init__.py
+++ b/spec/API_specification/dataframe_api/__init__.py
@@ -40,6 +40,7 @@
     "Duration",
     "String",
     "is_dtype",
+    "DatetimeAccessor",
 ]
 
 
diff --git a/spec/API_specification/dataframe_api/column_object.py b/spec/API_specification/dataframe_api/column_object.py
index 98f58410..61710865 100644
--- a/spec/API_specification/dataframe_api/column_object.py
+++ b/spec/API_specification/dataframe_api/column_object.py
@@ -8,7 +8,7 @@
     from ._types import NullType, Scalar, DType, Namespace
 
 
-__all__ = ['Column']
+__all__ = ['Column', 'DatetimeAccessor']
 
 
 class Column:
@@ -767,7 +767,7 @@ def rename(self, name: str) -> Column:
         ...
 
     @property
-    def dt(self) -> DatetimeAccessor:
+    def dt(self) -> "DatetimeAccessor":
         """
         Return accessor with functions which work on temporal dtypes.
         """

From f231d1f774443b8fb1cdfefd4309c760be8f1b83 Mon Sep 17 00:00:00 2001
From: MarcoGorelli <33491632+MarcoGorelli@users.noreply.github.com>
Date: Tue, 17 Oct 2023 09:45:26 +0300
Subject: [PATCH 4/7] remove .dt accessor, specify integerness of return
 columns

---
 .../dataframe_api/column_object.py            | 43 +++++++++++--------
 1 file changed, 24 insertions(+), 19 deletions(-)

diff --git a/spec/API_specification/dataframe_api/column_object.py b/spec/API_specification/dataframe_api/column_object.py
index 61710865..8c3032c9 100644
--- a/spec/API_specification/dataframe_api/column_object.py
+++ b/spec/API_specification/dataframe_api/column_object.py
@@ -766,71 +766,76 @@ def rename(self, name: str) -> Column:
         """
         ...
 
-    @property
-    def dt(self) -> "DatetimeAccessor":
-        """
-        Return accessor with functions which work on temporal dtypes.
-        """
-        ...
-
-class DatetimeAccessor:
-    """
-    Method which operate on temporal Columns.
-    """
 
     def year(self) -> Column:
         """
-        Return 'year' component of each element.
+        Return 'year' component of each element of `Date` and `Datetime` columns.
         
         For example, return 1981 for 1981-01-02T12:34:56.123456.
+
+        Return column should be of (signed) integer dtype.
         """
 
     def month(self) -> Column:
         """
-        Return 'month' component of each element.
+        Return 'month' component of each element of `Date` and `Datetime` columns.
         
         For example, return 1 for 1981-01-02T12:34:56.123456.
+
+        Return column should be of integer dtype (signed or unsigned).
         """
 
     def day(self) -> Column:
         """
-        Return 'day' component of each element.
+        Return 'day' component of each element of `Date` and `Datetime` columns.
         
         For example, return 2 for 1981-01-02T12:34:56.123456.
+
+        Return column should be of integer dtype (signed or unsigned).
         """
 
     def hour(self) -> Column:
         """
-        Return 'hour' component of each element.
+        Return 'hour' component of each element of `Date` and `Datetime` columns.
         
         For example, return 12 for 1981-01-02T12:34:56.123456.
+
+        Return column should be of integer dtype (signed or unsigned).
         """
 
     def minute(self) -> Column:
         """
-        Return 'minute' component of each element.
+        Return 'minute' component of each element of `Date` and `Datetime` columns.
         
         For example, return 34 for 1981-01-02T12:34:56.123456.
+
+        Return column should be of integer dtype (signed or unsigned).
         """
 
     def second(self) -> Column:
         """
-        Return 'second' component of each element.
+        Return 'second' component of each element of `Date` and `Datetime` columns.
         
         For example, return 56 for 1981-01-02T12:34:56.123456.
+
+        Return column should be of integer dtype (signed or unsigned).
         """
 
     def microsecond(self) -> Column:
         """
-        Return number of microseconds since last second, for each element.
+        Return number of microseconds since last second, for each element of `Date` and `Datetime` columns.
 
         For example, return 123456 for 1981-01-02T12:34:56.123456.
+
+        Return column should be of integer dtype (signed or unsigned).
         """
     
     def iso_weekday(self) -> Column:
         """
-        Return ISO weekday for each element.
+        Return ISO weekday for each element of `Date` and `Datetime` columns.
 
         Note that Monday=1, ..., Sunday=7.
+
+        Return column should be of integer dtype (signed or unsigned).
         """
 

From 987d12e2b8a8e0a287118dc3f467b9b3fe1c2bde Mon Sep 17 00:00:00 2001
From: MarcoGorelli <33491632+MarcoGorelli@users.noreply.github.com>
Date: Thu, 26 Oct 2023 10:57:18 +0100
Subject: [PATCH 5/7] fixup

---
 .../dataframe_api/column_object.py            | 69 +++++++++++++++----
 .../dataframe_api/dataframe_object.py         |  3 +
 2 files changed, 59 insertions(+), 13 deletions(-)

diff --git a/spec/API_specification/dataframe_api/column_object.py b/spec/API_specification/dataframe_api/column_object.py
index f0d8d710..638381eb 100644
--- a/spec/API_specification/dataframe_api/column_object.py
+++ b/spec/API_specification/dataframe_api/column_object.py
@@ -2,14 +2,12 @@
 
 from typing import Any,NoReturn, TYPE_CHECKING, Literal, Protocol
 
-from datetime import timedelta
-
 if TYPE_CHECKING:
     from .typing import NullType, Scalar, DType, Namespace
     from typing_extensions import Self
 
 
-__all__ = ['Column', 'DatetimeAccessor']
+__all__ = ['Column']
 
 
 class Column(Protocol):
@@ -34,8 +32,8 @@ def __column_namespace__(self) -> Namespace:
             attribute. It may contain other public names as well, but it is
             recommended to only include those names that are part of the
             specification.
-
         """
+        ...
     
     @property
     def column(self) -> Any:
@@ -54,6 +52,7 @@ def __len__(self) -> int:
         """
         Return the number of rows.
         """
+        ...
 
     def __iter__(self) -> NoReturn:
         """
@@ -68,10 +67,11 @@ def __iter__(self) -> NoReturn:
         raise NotImplementedError("'__iter__' is intentionally not implemented.")
 
     @property
-    def dtype(self) -> Any:
+    def dtype(self) -> DType:
         """
         Return data type of column.
         """
+        ...
 
     def get_rows(self, indices: Self) -> Self:
         """
@@ -215,6 +215,7 @@ def __eq__(self, other: Self | Scalar) -> Self:  # type: ignore[override]
         -------
         Column
         """
+        ...
 
     def __ne__(self, other: Self | Scalar) -> Self:  # type: ignore[override]
         """
@@ -233,6 +234,7 @@ def __ne__(self, other: Self | Scalar) -> Self:  # type: ignore[override]
         -------
         Column
         """
+        ...
 
     def __ge__(self, other: Self | Scalar) -> Self:
         """
@@ -249,6 +251,7 @@ def __ge__(self, other: Self | Scalar) -> Self:
         -------
         Column
         """
+        ...
 
     def __gt__(self, other: Self | Scalar) -> Self:
         """
@@ -265,6 +268,7 @@ def __gt__(self, other: Self | Scalar) -> Self:
         -------
         Column
         """
+        ...
 
     def __le__(self, other: Self | Scalar) -> Self:
         """
@@ -281,6 +285,7 @@ def __le__(self, other: Self | Scalar) -> Self:
         -------
         Column
         """
+        ...
 
     def __lt__(self, other: Self | Scalar) -> Self:
         """
@@ -297,6 +302,7 @@ def __lt__(self, other: Self | Scalar) -> Self:
         -------
         Column
         """
+        ...
 
     def __and__(self, other: Self | bool) -> Self:
         """
@@ -318,6 +324,7 @@ def __and__(self, other: Self | bool) -> Self:
         ValueError
             If `self` or `other` is not boolean.
         """
+        ...
 
     def __or__(self, other: Self | bool) -> Self:
         """
@@ -339,6 +346,7 @@ def __or__(self, other: Self | bool) -> Self:
         ValueError
             If `self` or `other` is not boolean.
         """
+        ...
 
     def __add__(self, other: Self | Scalar) -> Self:
         """
@@ -355,6 +363,7 @@ def __add__(self, other: Self | Scalar) -> Self:
         -------
         Column
         """
+        ...
 
     def __sub__(self, other: Self | Scalar) -> Self:
         """
@@ -371,6 +380,7 @@ def __sub__(self, other: Self | Scalar) -> Self:
         -------
         Column
         """
+        ...
 
     def __mul__(self, other: Self | Scalar) -> Self:
         """
@@ -387,6 +397,7 @@ def __mul__(self, other: Self | Scalar) -> Self:
         -------
         Column
         """
+        ...
 
     def __truediv__(self, other: Self | Scalar) -> Self:
         """
@@ -403,6 +414,7 @@ def __truediv__(self, other: Self | Scalar) -> Self:
         -------
         Column
         """
+        ...
 
     def __floordiv__(self, other: Self | Scalar) -> Self:
         """
@@ -419,6 +431,7 @@ def __floordiv__(self, other: Self | Scalar) -> Self:
         -------
         Column
         """
+        ...
 
     def __pow__(self, other: Self | Scalar) -> Self:
         """
@@ -439,6 +452,7 @@ def __pow__(self, other: Self | Scalar) -> Self:
         -------
         Column
         """
+        ...
 
     def __mod__(self, other: Self | Scalar) -> Self:
         """
@@ -455,6 +469,7 @@ def __mod__(self, other: Self | Scalar) -> Self:
         -------
         Column
         """
+        ...
 
     def __divmod__(self, other: Self | Scalar) -> tuple[Column, Column]:
         """
@@ -471,6 +486,7 @@ def __divmod__(self, other: Self | Scalar) -> tuple[Column, Column]:
         -------
         Column
         """
+        ...
 
     def __radd__(self, other: Self | Scalar) -> Self:
         ...
@@ -500,6 +516,7 @@ def __invert__(self) -> Self:
         ValueError
             If any of the Column's columns is not boolean.
         """
+        ...
 
     def any(self, *, skip_nulls: bool = True) -> bool | NullType:
         """
@@ -510,6 +527,7 @@ def any(self, *, skip_nulls: bool = True) -> bool | NullType:
         ValueError
             If column is not boolean.
         """
+        ...
 
     def all(self, *, skip_nulls: bool = True) -> bool | NullType:
         """
@@ -520,18 +538,21 @@ def all(self, *, skip_nulls: bool = True) -> bool | NullType:
         ValueError
             If column is not boolean.
         """
+        ...
 
     def min(self, *, skip_nulls: bool = True) -> Scalar | NullType:
         """
         Reduction returns a scalar. Any data type that supports comparisons
         must be supported. The returned value has the same dtype as the column.
         """
+        ...
 
     def max(self, *, skip_nulls: bool = True) -> Scalar | NullType:
         """
         Reduction returns a scalar. Any data type that supports comparisons
         must be supported. The returned value has the same dtype as the column.
         """
+        ...
 
     def sum(self, *, skip_nulls: bool = True) -> Scalar | NullType:
         """
@@ -539,12 +560,14 @@ def sum(self, *, skip_nulls: bool = True) -> Scalar | NullType:
         datetime data types. The returned value has the same dtype as the
         column.
         """
+        ...
 
     def prod(self, *, skip_nulls: bool = True) -> Scalar | NullType:
         """
         Reduction returns a scalar. Must be supported for numerical data types.
         The returned value has the same dtype as the column.
         """
+        ...
 
     def median(self, *, skip_nulls: bool = True) -> Scalar | NullType:
         """
@@ -553,6 +576,7 @@ def median(self, *, skip_nulls: bool = True) -> Scalar | NullType:
         datetime (with the appropriate timedelta format string) for datetime
         dtypes.
         """
+        ...
 
     def mean(self, *, skip_nulls: bool = True) -> Scalar | NullType:
         """
@@ -561,6 +585,7 @@ def mean(self, *, skip_nulls: bool = True) -> Scalar | NullType:
         datetime (with the appropriate timedelta format string) for datetime
         dtypes.
         """
+        ...
 
     def std(self, *, correction: int | float = 1, skip_nulls: bool = True) -> Scalar | NullType:
         """
@@ -587,6 +612,7 @@ def std(self, *, correction: int | float = 1, skip_nulls: bool = True) -> Scalar
         skip_nulls
             Whether to skip null values.
         """
+        ...
 
     def var(self, *, correction: int | float = 1, skip_nulls: bool = True) -> Scalar | NullType:
         """
@@ -604,18 +630,21 @@ def var(self, *, correction: int | float = 1, skip_nulls: bool = True) -> Scalar
         skip_nulls
             Whether to skip null values.
         """
+        ...
 
     def cumulative_max(self) -> Self:
         """
         Reduction returns a Column. Any data type that supports comparisons
         must be supported. The returned value has the same dtype as the column.
         """
+        ...
 
     def cumulative_min(self) -> Self:
         """
         Reduction returns a Column. Any data type that supports comparisons
         must be supported. The returned value has the same dtype as the column.
         """
+        ...
 
     def cumulative_sum(self) -> Self:
         """
@@ -623,6 +652,7 @@ def cumulative_sum(self) -> Self:
         datetime data types. The returned value has the same dtype as the
         column.
         """
+        ...
 
     def cumulative_prod(self) -> Self:
         """
@@ -630,6 +660,7 @@ def cumulative_prod(self) -> Self:
         datetime data types. The returned value has the same dtype as the
         column.
         """
+        ...
 
     def is_null(self) -> Self:
         """
@@ -649,6 +680,7 @@ def is_null(self) -> Self:
         May optionally include 'NaT' values (if present in an implementation),
         but note that the Standard makes no guarantees about them.
         """
+        ...
 
     def is_nan(self) -> Self:
         """
@@ -668,6 +700,7 @@ def is_nan(self) -> Self:
         Does *not* include 'missing' or 'null' entries.
         In particular, does not check for `np.timedelta64('NaT')`.
         """
+        ...
 
     def is_in(self, values: Self) -> Self:
         """
@@ -686,6 +719,7 @@ def is_in(self, values: Self) -> Self:
         -------
         Column
         """
+        ...
 
     def unique_indices(self, *, skip_nulls: bool = True) -> Self:
         """
@@ -768,6 +802,7 @@ def to_array(self) -> Any:
         understanding that consuming libraries would then use the
         ``array-api-compat`` package to convert it to a Standard-compliant array.
         """
+        ...
 
     def rename(self, name: str) -> Self:
         """
@@ -786,7 +821,7 @@ def rename(self, name: str) -> Self:
         ...
 
 
-    def year(self) -> Column:
+    def year(self) -> Self:
         """
         Return 'year' component of each element of `Date` and `Datetime` columns.
         
@@ -794,8 +829,9 @@ def year(self) -> Column:
 
         Return column should be of (signed) integer dtype.
         """
+        ...
 
-    def month(self) -> Column:
+    def month(self) -> Self:
         """
         Return 'month' component of each element of `Date` and `Datetime` columns.
         
@@ -803,8 +839,9 @@ def month(self) -> Column:
 
         Return column should be of integer dtype (signed or unsigned).
         """
+        ...
 
-    def day(self) -> Column:
+    def day(self) -> Self:
         """
         Return 'day' component of each element of `Date` and `Datetime` columns.
         
@@ -812,8 +849,9 @@ def day(self) -> Column:
 
         Return column should be of integer dtype (signed or unsigned).
         """
+        ...
 
-    def hour(self) -> Column:
+    def hour(self) -> Self:
         """
         Return 'hour' component of each element of `Date` and `Datetime` columns.
         
@@ -821,8 +859,9 @@ def hour(self) -> Column:
 
         Return column should be of integer dtype (signed or unsigned).
         """
+        ...
 
-    def minute(self) -> Column:
+    def minute(self) -> Self:
         """
         Return 'minute' component of each element of `Date` and `Datetime` columns.
         
@@ -830,8 +869,9 @@ def minute(self) -> Column:
 
         Return column should be of integer dtype (signed or unsigned).
         """
+        ...
 
-    def second(self) -> Column:
+    def second(self) -> Self:
         """
         Return 'second' component of each element of `Date` and `Datetime` columns.
         
@@ -839,8 +879,9 @@ def second(self) -> Column:
 
         Return column should be of integer dtype (signed or unsigned).
         """
+        ...
 
-    def microsecond(self) -> Column:
+    def microsecond(self) -> Self:
         """
         Return number of microseconds since last second, for each element of `Date` and `Datetime` columns.
 
@@ -848,8 +889,9 @@ def microsecond(self) -> Column:
 
         Return column should be of integer dtype (signed or unsigned).
         """
+        ...
     
-    def iso_weekday(self) -> Column:
+    def iso_weekday(self) -> Self:
         """
         Return ISO weekday for each element of `Date` and `Datetime` columns.
 
@@ -857,4 +899,5 @@ def iso_weekday(self) -> Column:
 
         Return column should be of integer dtype (signed or unsigned).
         """
+        ...
 
diff --git a/spec/API_specification/dataframe_api/dataframe_object.py b/spec/API_specification/dataframe_api/dataframe_object.py
index c577a853..7d4d5c41 100644
--- a/spec/API_specification/dataframe_api/dataframe_object.py
+++ b/spec/API_specification/dataframe_api/dataframe_object.py
@@ -64,6 +64,7 @@ def shape(self) -> tuple[int, int]:
         """
         Return number of rows and number of columns.
         """
+        ...
 
     def group_by(self, *keys: str) -> GroupBy:
         """
@@ -463,6 +464,7 @@ def __and__(self, other: bool) -> Self:
         ValueError
             If `self` or `other` is not boolean.
         """
+        ...
 
     def __or__(self, other: bool) -> Self:
         """
@@ -483,6 +485,7 @@ def __or__(self, other: bool) -> Self:
         ValueError
             If `self` or `other` is not boolean.
         """
+        ...
 
     def __add__(self, other: Scalar) -> Self:
         """

From a43ad4a4f37db15b6da66babfe6af5b058fb7a74 Mon Sep 17 00:00:00 2001
From: MarcoGorelli <33491632+MarcoGorelli@users.noreply.github.com>
Date: Sat, 7 Oct 2023 19:28:46 +0300
Subject: [PATCH 6/7] add dt.floor

---
 .../dataframe_api/column_object.py            | 35 +++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/spec/API_specification/dataframe_api/column_object.py b/spec/API_specification/dataframe_api/column_object.py
index 638381eb..8355266b 100644
--- a/spec/API_specification/dataframe_api/column_object.py
+++ b/spec/API_specification/dataframe_api/column_object.py
@@ -901,3 +901,38 @@ def iso_weekday(self) -> Self:
         """
         ...
 
+    def floor(self, frequency: str) -> Column:
+        """
+        Return floor of each element according to the specified frequency.
+
+        Flooring is done according to local time. For example,
+        for a ``Datetime('us', 'Europe/London')`` column,
+        ``"2020-10-25T00:30:00 BST"`` floored by ``"1day"`` gives
+        ``"2020-10-25T00:00:00 BST"``.
+        Behaviours in the face of ambiguous and non-existent times are
+        currently unspecified and may vary across implementations.
+
+        Flooring by non-fixed durations (e.g. calendar month) are not supported.
+        Note that flooring by ``timedelta(days=1)`` is equivalent to flooring
+        by ``timedelta(hours=24)``.
+
+        Parameters
+        ----------
+        freq : str
+            Frequency to floor by. Can be constructed using the following string
+            language:
+
+            - "1day"
+            - "1hour"
+            - "1minute"
+            - "1second"
+            - "1millisecond"
+            - "1microsecond"
+
+        Examples
+        --------
+        Roll each datetime back to the beginning of the day:
+
+        >>> column: Column
+        >>> column.dt.floor("1day")
+        """

From 6b04f771b231f4d642bfe0555ba0dfa3c1cea810 Mon Sep 17 00:00:00 2001
From: MarcoGorelli <33491632+MarcoGorelli@users.noreply.github.com>
Date: Thu, 26 Oct 2023 11:10:42 +0100
Subject: [PATCH 7/7] clarify

---
 spec/API_specification/column_object.rst      |  2 --
 .../dataframe_api/column_object.py            | 23 ++++++++++++++-----
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/spec/API_specification/column_object.rst b/spec/API_specification/column_object.rst
index 5ff16633..3201b500 100644
--- a/spec/API_specification/column_object.rst
+++ b/spec/API_specification/column_object.rst
@@ -10,5 +10,3 @@ behavior.
 .. currentmodule:: dataframe_api
 
 .. autoclass:: Column
-
-.. autoclass:: DatetimeAccessor
diff --git a/spec/API_specification/dataframe_api/column_object.py b/spec/API_specification/dataframe_api/column_object.py
index 8355266b..632580f5 100644
--- a/spec/API_specification/dataframe_api/column_object.py
+++ b/spec/API_specification/dataframe_api/column_object.py
@@ -901,7 +901,7 @@ def iso_weekday(self) -> Self:
         """
         ...
 
-    def floor(self, frequency: str) -> Column:
+    def floor(self, frequency: str) -> Self:
         """
         Return floor of each element according to the specified frequency.
 
@@ -922,12 +922,22 @@ def floor(self, frequency: str) -> Column:
             Frequency to floor by. Can be constructed using the following string
             language:
 
+            - "<n>day(s)"
+            - "<n>hour(s)"
+            - "<n>minute(s)"
+            - "<n>second(s)"
+            - "<n>millisecond(s)"
+            - "<n>microsecond(s)"
+
+            where ``<n>`` is a positive integer and the trailing (s) is
+            optional.
+            Multiple frequencies can be specified, separated by blank spaces.
+
+            Examples of valid inputs are:
+
             - "1day"
-            - "1hour"
-            - "1minute"
-            - "1second"
-            - "1millisecond"
-            - "1microsecond"
+            - "1day 1hour"
+            - "1day 2hours 3minutes 4seconds 5milliseconds 6microseconds"
 
         Examples
         --------
@@ -936,3 +946,4 @@ def floor(self, frequency: str) -> Column:
         >>> column: Column
         >>> column.dt.floor("1day")
         """
+        ...