def exception(self):
        """ Try retrieving the last subprocess exception.
            If set, the exception is returned. Otherwise None is returned.
        """
        if self._exception is not None:
            return self._exception
        try:
            exc, tblines = self.exc_queue.get_nowait()
        except Empty:
            self._exception, self.tb_lines = None, None
        else:
            # Raise any exception that the subprocess encountered and sent.
            self._exception, self.tb_lines = exc, tblines
        return self._exception
def exception ( self ) : if self . _exception is not None : return self . _exception try : exc , tblines = self . exc_queue . get_nowait ( ) except Empty : self . _exception , self . tb_lines = None , None else : self . _exception , self . tb_lines = exc , tblines return self . _exception
Try retrieving the last subprocess exception.
            If set, the exception is returned. Otherwise None is returned.