nd ``level``.
as_index : bool, default True
    Return object with group labels as the
    index. Only relevant for DataFrame input. as_index=False is
    effectively "SQL-style" grouped output. This argument has no effect
    on filtrations (see the `filtrations in the user guide
    <https://pandas.pydata.org/docs/dev/user_guide/groupby.html#filtration>`_),
    such as ``head()``, ``tail()``, ``nth()`` and in transformations
    (see the `transformations in the user guide
    <https://pandas.pydata.org/docs/dev/user_guide/groupby.html#transformation>`_).
sort : bool, default True
    Sort group keys. Get better performance by turning this off.
    Note this does not influence the order of observations within each
    group. Groupby preserves the order of rows within each group. If False,
    the groups will appear in the same order as they did in the original DataFrame.
    This argument has no effect on filtrations (see the `filtrations in the user guide
    <https://pandas.pydata.org/docs/dev/user_guide/groupby.html#filtration>`_),
    such as ``head()``, ``tail()``, ``nth()`` and in transformations
    (see the `transformations in the user guide
    <https://pandas.pydata.org/docs/dev/user_guide/groupby.html#transformation>`_).

    .. versionchanged:: 2.0.0

        Specifying ``sort=False`` with an ordered categorical grouper will no
        longer sort the values.

group_keys : bool, default True
    When calling apply and the ``by`` argument produces a like-indexed
    (i.e. :ref:`a transform <groupby.transform>`) result, add group keys to
    index to identify pieces. By default group keys are not included
    when the result's index (and column) labels match the inputs, and
    are included otherwise.

    .. versionchanged:: 1.5.0

       Warns that ``group_keys`` will no longer be ignored when the
       result from ``apply`` is a like-indexed Series or DataFrame.
       Specify ``group_keys`` explicitly to include the group keys or
       not.

    .. versionchanged:: 2.0.0

       ``group_keys`` now defaults to ``True``.

observed : bool, default False
    This only applies if any of the groupers are Categoricals.
    If True: only show observed values for categorical groupers.
    If False: show all values for categorical groupers.

    .. deprecated:: 2.1.0

        The default value will change to True in a future version of pandas.

dropna : bool, default True
    If True, and if group keys contain NA values, NA values together
    with row/column will be dropped.
    If False, NA values will also be treated as the key in groups.

Returns
-------
pandas.api.typing.%(klass)sGroupBy
    Returns a groupby object that contains information about the groups.

See Also
--------
resample : Convenience method for frequency conversion and resampling
    of time series.

Notes
-----
See the `user guide
<https://pandas.pydata.org/pandas-docs/stable/groupby.html>`__ for more
detailed usage and examples, including splitting an object into groups,
iterating through groups, selecting a group, aggregation, and more.
