websocket-client: on_close() doesn't get called after calling close()

code just like:

class MyWS(object):
    def __init__(self):
        self._ws = None
    def on_close(self):
        print("closed")

    def run(self):
        try:
            # websocket.enableTrace(True)
            self._ws = websocket.WebSocketApp(*******)
            self._ws.on_close = self.on_close
            self._ws.run_forever()
        except Exception:
            pass

After calling run() above and connection successful, I call self._ws.close() somewhere, But on_close() func doesn’t get called. What’s wrong? In _app.py:

    def close(self, **kwargs):
        """
        close websocket connection.
        """
        self.keep_running = False
        if self.sock:
            self.sock.close(**kwargs)
            self.sock = None

As above, After calling self._ws.close(), self.keep_running is set to False, Then in _app.py:

class Dispatcher:
    def __init__(self, app, ping_timeout):
        self.app = app
        self.ping_timeout = ping_timeout

    def read(self, sock, read_callback, check_callback):
        while self.app.keep_running:
            r, w, e = select.select(
                    (self.app.sock.sock, ), (), (), self.ping_timeout)
            if r:
                if not read_callback():
                    break
            check_callback()

the while loop in read() func will be over according to self.keep_running. After dispatcher.read(), nothing is going to be done in run_forever() func.

Is there some suggestions? Thks.