def get_unknown_topics(self, lang):
        """Return the topics remaining to learn by a user in a language."""
        return [topic['title']
                for topic in self.user_data.language_data[lang]['skills']
                if not topic['learned']]
def get_unknown_topics ( self , lang ) : return [ topic [ 'title' ] for topic in self . user_data . language_data [ lang ] [ 'skills' ] if not topic [ 'learned' ] ]
Return the topics remaining to learn by a user in a language.