python - open PyQt window from thread -

i'am trying python app combine tornado websocket , pyqt windows
need open pyqt window when receive message websocket, program fall down. elegant way how it?

controller:

class mainwindow(qtwidgets.qwidget, widget.ui_form):         def __init__(self):         super(self.__class__, self).__init__()         self.setupui(self)         self.message_window = none   class message(qtwidgets.qwidget, message.ui_form):     def __init__(self, msg):         super(self.__class__, self).__init__()         self.setupui(self, msg)    if __name__ == "__main__":     app = qtwidgets.qapplication(sys.argv)     window = mainwindow()     window.show()     s = server(window)     s.start()     exit(app.exec_()) 

server:

class server(qtcore.qthread): def __init__(self, main_window):     qtcore.qthread.__init__(self)     self.msg_win = main_window.message_window  def run(self):     self.msg_win = controller.message("test")     self.msg_win.show()     *** starting tornado *** 

thanks help