def _command_options(self):
        """Return the options dict for the aggregation command."""
        options = {}
        if self._max_await_time_ms is not None:
            options["maxAwaitTimeMS"] = self._max_await_time_ms
        if self._batch_size is not None:
            options["batchSize"] = self._batch_size
        return options
Return the options dict for the aggregation command.
stackoverflow/venv/lib/python3.6/site-packages/pymongo/change_stream.py