def GetSources(self, event):
    """Determines the the short and long source for an event object.

    Args:
      event (EventObject): event.

    Returns:
      tuple(str, str): short and long source string.

    Raises:
      WrongFormatter: if the event object cannot be formatted by the formatter.
    """
    if self.DATA_TYPE != event.data_type:
      raise errors.WrongFormatter('Unsupported data type: {0:s}.'.format(
          event.data_type))

    source_long = getattr(event, 'source_long', 'UNKNOWN')
    source_append = getattr(event, 'source_append', None)
    if source_append:
      source_long = '{0:s} {1:s}'.format(source_long, source_append)

    return self.SOURCE_SHORT, source_long
Determines the the short and long source for an event object.

    Args:
      event (EventObject): event.

    Returns:
      tuple(str, str): short and long source string.

    Raises:
      WrongFormatter: if the event object cannot be formatted by the formatter.