def _apply_index_days(self, i, roll):
nanos = (roll % <NUM_LIT:2>) * Timedelta(days=self.day_of_month - <NUM_LIT:1>).value<EOL>return i + nanos.astype('<STR_LIT>')<EOL>
Add days portion of offset to DatetimeIndex i.

Parameters
----------
i : DatetimeIndex
roll : ndarray[int64_t]

Returns
-------
result : DatetimeIndex