Returns a DatetimeIndex representing all the minutes in this calendar.

def all_minutes(self):
        """
        Returns a DatetimeIndex representing all the minutes in this calendar.
        """
        opens_in_ns = self._opens.values.astype(
            'datetime64[ns]',
        ).view('int64')

        closes_in_ns = self._closes.values.astype(
            'datetime64[ns]',
        ).view('int64')

        return DatetimeIndex(
            compute_all_minutes(opens_in_ns, closes_in_ns),
            tz=UTC,
        )