observer.py 文件源码

def emit(self, *args, **kwargs):
        '''
        Emit the event with the given positional and keyword arguments.

        Returns a dict mapping event listeners to their results, or an exception
        instance if calling the listener raised one.
        '''
        results = {}
        # kwargs['__event__'] = self
        for listener in self._listeners.values():
            if isinstance(listener, (weakref.ReferenceType, BoundMethodWeakref)):
                listener = listener()
                if listener is None:
                    # This shouldn't happen, but we need to guard for it.
                    continue
            try:
                results[listener] = listener(*args, **kwargs)
            except Exception as e:
                if self._abort_on_error:
                    raise
                results[listener] = e
                print("error in listener: %s".format(listener))
                import traceback
                traceback.print_exc()
        return results