def CopyToDateTimeStringISO8601(self):
date_time_string = self.CopyToDateTimeString()<EOL>if date_time_string:<EOL><INDENT>date_time_string = date_time_string.replace('<STR_LIT:U+0020>', '<STR_LIT:T>')<EOL>date_time_string = '<STR_LIT>'.format(date_time_string)<EOL><DEDENT>return date_time_string<EOL>
Copies the date time value to an ISO 8601 date and time string.

        Returns:
          str: date and time value formatted as an ISO 8601 date and time string or
              None if the timestamp cannot be copied to a date and time string.