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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def commit(self):
 """Commit the changes accumulated in this batch. Returns: List[google.cloud.proto.firestore.v1beta1.\ to the changes committed, returned in the same order as the changes were applied to this batch. A write result contains an ``update_time`` field. """

        commit_response = self._client._firestore_api.commit(
            self._client._database_string,
            self._write_pbs,
            transaction=None,
            metadata=self._client._rpc_metadata,
        )

        self._write_pbs = []
        self.write_results = results = list(commit_response.write_results)
        self.commit_time = commit_response.commit_time
        return results