docs: def _append_date(self, value, _file):
          """Call this function to write date contents.
  
          Keyword arguments:
              * value - dict, content to be dumped
              * _file - FileIO, output file
  
          """
          _tabs = '\t' * self._tctr
          _text = value.strftime('%Y-%m-%dT%H:%M:%S.%fZ')
          _labs = '{tabs}<date>{text}</date>\n'.format(tabs=_tabs, text=_text)
          _file.write(_labs)