[1, 1, 2, 2])
    >>> grouped.transform(lambda x: (x - x.mean()) / x.std())
        Falcon    0.707107
        Falcon   -0.707107
        Parrot    0.707107
        Parrot   -0.707107
        Name: Max Speed, dtype: float64

    Broadcast result of the transformation

    >>> grouped.transform(lambda x: x.max() - x.min())
    Falcon    40.0
    Falcon    40.0
    Parrot    10.0
    Parrot    10.0
    Name: Max Speed, dtype: float64

    >>> grouped.transform("mean")
    Falcon    370.0
    Falcon    370.0
    Parrot     25.0
    Parrot     25.0
    Name: Max Speed, dtype: float64

    .. versionchanged:: 1.3.0

    The resulting dtype will reflect the return value of the passed ``func``,
    for example:

    >>> grouped.transform(lambda x: x.astype(int).max())
    Falcon    390
    Falcon    390
    Parrot     30
    Parrot     30
    Name: Max Speed, dtype: int64
    ©