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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def pad(self, sid, date):
 """ 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` """

        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)