async_utils.py 文件源码

def await_exception(self, timeout=None):  # pragma: no-cover
        """
        Return the exception raised by the call that the future represents.

        Args:
            timeout: The number of seconds to wait for the exception if the
                future isn't done. If None, then there is no limit on the wait
                time.

        Returns:
            The exception raised by the call that the future represents or None
            if the call completed without raising.

        Raises:
            CancelledError: If the future was cancelled.
            TimeoutError: If the future didn't finish executing before the
            given  timeout.
        """
        self._wait_for_done(timeout)
        return self.exception()