def _change_stream_options(self):
        """Return the options dict for the $changeStream pipeline stage."""
        options = {}
        if self._full_document is not None:
            options['fullDocument'] = self._full_document

        resume_token = self.resume_token
        if resume_token is not None:
            if self._uses_start_after:
                options['startAfter'] = resume_token
            if self._uses_resume_after:
                options['resumeAfter'] = resume_token

        if self._start_at_operation_time is not None:
            options['startAtOperationTime'] = self._start_at_operation_time
        return options
Return the options dict for the $changeStream pipeline stage.
stackoverflow/venv/lib/python3.6/site-packages/pymongo/change_stream.py