code: def CopyToDateTimeStringISO8601(self):
      
      date_time_string = self.CopyToDateTimeString()
      if date_time_string:
        date_time_string = date_time_string.replace(' ', 'T')
        date_time_string = '{0:s}Z'.format(date_time_string)
      return date_time_string
docs: 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.