def AddEventTags(self, event_tags):
    """Adds event tags.

    Args:
      event_tags (list[EventTag]): event tags.

    Raises:
      IOError: when the storage file is closed or read-only or
          if the event tags cannot be serialized.
      OSError: when the storage file is closed or read-only or
          if the event tags cannot be serialized.
    """
    self._RaiseIfNotWritable()

    for event_tag in event_tags:
      self.AddEventTag(event_tag)
Adds event tags.

    Args:
      event_tags (list[EventTag]): event tags.

    Raises:
      IOError: when the storage file is closed or read-only or
          if the event tags cannot be serialized.
      OSError: when the storage file is closed or read-only or
          if the event tags cannot be serialized.