code: def _FormatMessages(self, format_string, short_format_string, event_values):
      
      message_string = self._FormatMessage(format_string, event_values)
  
      if short_format_string:
        short_message_string = self._FormatMessage(
            short_format_string, event_values)
      else:
        short_message_string = message_string
  
      # Truncate the short message string if necessary.
      if len(short_message_string) > 80:
        short_message_string = '{0:s}...'.format(short_message_string[:77])
  
      return message_string, short_message_string
docs: Determines the formatted message strings.
  
      Args:
        format_string (str): message format string.
        short_format_string (str): short message format string.
        event_values (dict[str, object]): event values.
  
      Returns:
        tuple(str, str): formatted message string and short message string.