def addSynonym(
            self, class_id, synonym, synonym_type=None):
        """
        Add the synonym as a property of the class cid.
        Assume it is an exact synonym, unless otherwise specified
        :param g:
        :param cid: class id
        :param synonym: the literal synonym label
        :param synonym_type: the CURIE of the synonym type (not the URI)
        :return:

        """

        if synonym_type is None:
            synonym_type = self.globaltt['has_exact_synonym']

        if synonym is not None:
            self.graph.addTriple(
                class_id, synonym_type, synonym, object_is_literal=True)
Add the synonym as a property of the class cid.
        Assume it is an exact synonym, unless otherwise specified
        :param g:
        :param cid: class id
        :param synonym: the literal synonym label
        :param synonym_type: the CURIE of the synonym type (not the URI)
        :return: