'Add the given track to library. Optional args will only be added if
:attr:`add_supports_tags_and_duration` has been set.
:param track: Track to add to the library
:type track: :class:`~mopidy.models.Track`
:param tags: All the tags the scanner found for the media. See
:mod:`mopidy.audio.utils` for details about the tags.
:type tags: dictionary of tag keys with a list of values.
:param duration: Duration of media in milliseconds or :class:`None` if
unknown
:type duration: :class:`int` or :class:`None`'

def add(self, track, tags=None, duration=None):

    raise NotImplementedError
