'Get a list of the currently available playlists.
Returns a list of :class:`~mopidy.models.Ref` objects referring to the
playlists. In other words, no information about the playlists\' content
is given.
:rtype: list of :class:`mopidy.models.Ref`
.. versionadded:: 1.0'

def as_list(self):

    futures = {backend: backend.playlists.as_list() for backend in set(self.backends.with_playlists.values())}
    results = []
    for (b, future) in futures.items():
        try:
            with _backend_error_handling(b, reraise=NotImplementedError):
                playlists = future.get()
                if (playlists is not None):
                    validation.check_instances(playlists, Ref)
                    results.extend(playlists)
        except NotImplementedError:
            backend_name = b.actor_ref.actor_class.__name__
            logger.warning(u'%s    does    not    implement    playlists.as_list().    Please    upgrade    it.', backend_name)
    return results
