Get the result of the operation, blocking if necessary.

        Args:
            timeout (int):
                How long (in seconds) to wait for the operation to complete.
                If None, wait indefinitely.

        Returns:
            google.protobuf.Message: The Operation's result.

        Raises:
            google.api_core.GoogleAPICallError: If the operation errors or if
                the timeout is reached before the operation completes.

def result(self, timeout=None):
        """Get the result of the operation, blocking if necessary.

        Args:
            timeout (int):
                How long (in seconds) to wait for the operation to complete.
                If None, wait indefinitely.

        Returns:
            google.protobuf.Message: The Operation's result.

        Raises:
            google.api_core.GoogleAPICallError: If the operation errors or if
                the timeout is reached before the operation completes.
        """
        self._blocking_poll(timeout=timeout)

        if self._exception is not None:
            # pylint: disable=raising-bad-type
            # Pylint doesn't recognize that this is valid in this case.
            raise self._exception

        return self._result