code: def pad(self, sid, date):
          
          table = self._ensure_ctable(sid)
  
          last_date = self.last_date_in_output_for_sid(sid)
  
          tds = self._session_labels
  
          if date <= last_date or date < tds[0]:
              # No need to pad.
              return
  
          if last_date == pd.NaT:
              # If there is no data, determine how many days to add so that
              # desired days are written to the correct slots.
              days_to_zerofill = tds[tds.slice_indexer(end=date)]
          else:
              days_to_zerofill = tds[tds.slice_indexer(
                  start=last_date + tds.freq,
                  end=date)]
  
          self._zerofill(table, len(days_to_zerofill))
  
          new_last_date = self.last_date_in_output_for_sid(sid)
          assert new_last_date == date, "new_last_date={0} != date={1}".format(
              new_last_date, date)
docs: Fill sid container with empty data through the specified date.
  
          If the last recorded trade is not at the close, then that day will be
          padded with zeros until its close. Any day after that (up to and
          including the specified date) will be padded with `minute_per_day`
          worth of zeros
  
          Parameters
          ----------
          sid : int
              The asset identifier for the data being written.
          date : datetime-like
              The date used to calculate how many slots to be pad.
              The padding is done through the date, i.e. after the padding is
              done the `last_date_in_output_for_sid` will be equal to `date`