code: def extend(self, records):
          
          fields = self.fields
          for record in records:
              record = _cast_record_to_str_tuple(record, fields)
              self._records.append(record)
docs: Add each record in *records* to the end of the table.
  
          Args:
              record: an iterable of :class:`Record` or other iterables
                  containing column values