on DatetimeIndex.

        >>> df = pd.DataFrame({'dates': pd.date_range("2017-03-30",
        ...                    periods=4)})
        >>> df.assign(quarter=df.dates.dt.quarter,
        ...           is_quarter_end=df.dates.dt.is_quarter_end)
               dates  quarter    is_quarter_end
        0 2017-03-30        1             False
        1 2017-03-31        1              True
        2 2017-04-01        2             False
        3 2017-04-02        2             False

        >>> idx = pd.date_range('2017-03-30', periods=4)
        >>> idx
        DatetimeIndex(['2017-03-30', '2017-03-31', '2017-04-01', '2017-04-02'],
                      dtype='datetime64[ns]', freq='D')

        >>> idx.is_quarter_end
        array([False,  True, False, False])
        r|