def start_batch_learning(self):
        """Begin a series of batch learn operations. Data will not be
        committed to the database until stop_batch_learning is
        called. Learn text using the normal learn(text) method."""
        self._learning = True

        self.graph.cursor().execute("PRAGMA journal_mode=memory")
        self.graph.drop_reply_indexes()
Begin a series of batch learn operations. Data will not be
        committed to the database until stop_batch_learning is
        called. Learn text using the normal learn(text) method.