code: def _datetime_for_table_name(self, table_name):
          
          m = self._table_re.match(table_name)
          dt = datetime.strptime(m.group(1), '%Y%m%d')
          return dt
docs: Return a :py:class:`datetime.datetime` object for the date of the
          data in the specified table name.
  
          :param table_name: name of the table
          :type table_name: str
          :return: datetime that the table holds data for
          :rtype: datetime.datetime