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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 delete(self, option=None):
 """Delete the current document in the Firestore database. Args: option (Optional[~.firestore_v1beta1.client.WriteOption]):
 A write option to make assertions / preconditions on the server state of the document before applying changes. Returns: google.protobuf.timestamp_pb2.Timestamp: The time that the delete request was received by the server. If the document did not exist when the delete was sent (i.e. nothing was deleted), this method will still succeed and will still return the time that the request was received by the server. """

        write_pb = _helpers.pb_for_delete(self._document_path, option)
        commit_response = self._client._firestore_api.commit(
            self._client._database_string,
            [write_pb],
            transaction=None,
            metadata=self._client._rpc_metadata,
        )

        return commit_response.commit_time