'Called whenever the current audio stream\'s tags change.
This event signals that some track metadata has been updated. This can
be metadata such as artists, titles, organization, or details about the
actual audio such as bit-rates, numbers of channels etc.
For the available tag keys please refer to GStreamer documentation for
tags.
*MAY* be implemented by actor.
:param tags: The tags that have just been updated.
:type tags: :class:`set` of strings'

def tags_changed(self, tags):

    pass
