def CopyToDateTimeString(self):
if self._number_of_seconds is None:<EOL><INDENT>return None<EOL><DEDENT>return '<STR_LIT>'.format(<EOL>self._time_elements_tuple[<NUM_LIT:0>], self._time_elements_tuple[<NUM_LIT:1>],<EOL>self._time_elements_tuple[<NUM_LIT:2>], self._time_elements_tuple[<NUM_LIT:3>],<EOL>self._time_elements_tuple[<NUM_LIT:4>], self._time_elements_tuple[<NUM_LIT:5>])<EOL>
Copies the time elements to a date and time string.

        Returns:
          str: date and time value formatted as: "YYYY-MM-DD hh:mm:ss" or None
              if time elements are missing.