Returns triple related to this node. Can filter on lang

        :param key: Predicate of the triple
        :param lang: Language of the triple if applicable
        :rtype: Literal or BNode or URIRef

def get(self, key, lang=None):
        """ Returns triple related to this node. Can filter on lang

        :param key: Predicate of the triple
        :param lang: Language of the triple if applicable
        :rtype: Literal or BNode or URIRef
        """
        if lang is not None:
            for o in self.graph.objects(self.asNode(), key):
                if o.language == lang:
                    yield o
        else:
            for o in self.graph.objects(self.asNode(), key):
                yield o