def GetFormatStringAttributeNames(self, event):
    """Retrieves the attribute names in the format string.

    Args:
      event (EventObject): event.

    Returns:
      list[str]: list containing the attribute names. If no event formatter to
          match the event can be found the function returns None.
    """
    event_formatter = self.GetEventFormatter(event)
    if not event_formatter:
      return None

    return event_formatter.GetFormatStringAttributeNames()
Retrieves the attribute names in the format string.

    Args:
      event (EventObject): event.

    Returns:
      list[str]: list containing the attribute names. If no event formatter to
          match the event can be found the function returns None.