def load_vocab(self, vocab_name, **kwargs):
        """ loads a vocabulary into the defintion triplestore

        args:
            vocab_name: the prefix, uri or filename of a vocabulary
        """
        log.setLevel(kwargs.get("log_level", self.log_level))

        vocab = self.get_vocab(vocab_name   , **kwargs)
        if vocab['filename'] in self.loaded:
            if self.loaded_times.get(vocab['filename'],
                    datetime.datetime(2001,1,1)).timestamp() \
                    < vocab['modified']:
                self.drop_file(vocab['filename'], **kwargs)
            else:
                return
        conn = kwargs.get("conn", self.conn)
        conn.load_data(graph=getattr(__NSM__.kdr, vocab['filename']).clean_uri,
                       data=vocab['data'],
                       datatype=vocab['filename'].split(".")[-1],
                       log_level=logging.WARNING)
        self.__update_time__(vocab['filename'], **kwargs)
        log.warning("\n\tvocab: '%s' loaded \n\tconn: '%s'",
                    vocab['filename'],
                    conn)
        self.loaded.append(vocab['filename'])
loads a vocabulary into the defintion triplestore

        args:
            vocab_name: the prefix, uri or filename of a vocabulary