'Check for video and languages validity in the Service
:param video: the video to check
:type video: :class:`~subliminal.videos.video`
:param languages: languages to check
:type languages: :class:`~subliminal.language.Language`
:rtype: bool'

@classmethod
def check_validity(cls, video, languages):

    languages = ((languages & cls.languages) - language_set(['Undetermined']))
    if (not languages):
        logger.debug((u'No    language    available    for    service    %s' % cls.__name__.lower()))
        return False
    if ((cls.require_video and (not video.exists)) or (not isinstance(video, tuple(cls.videos)))):
        logger.debug((u'%r    is    not    valid    for    service    %s' % (video, cls.__name__.lower())))
        return False
    return True
