'Computes the album gain of the given album, returns an
AlbumGain object.'

def compute_album_gain(self, album):

    supported_items = list(filter(self.format_supported, album.items()))
    if (len(supported_items) != len(album.items())):
        self._log.debug(u'tracks    are    of    unsupported    format')
        return AlbumGain(None, [])
    output = self.compute_gain(supported_items, True)
    return AlbumGain(output[(-1)], output[:(-1)])
