multithreading - Python : How to pause and resume threads -

i have tornado server websockets:

class sockhandler(sockjsconnection):      def on_open(self, request):         clients.add(self)       def on_message(self, message):          if (message == 'start'):             self.send({'message' : start_msg})              thr = threading.thread(target=func_with_loop, args=(self.on_result,)).start()          if (message == 'next'):             # resume 'thr'       def on_result(self, response):         self.send(response)         # pause 'thr'      def on_error(self, e):         print(e)      def on_close(self):         clients.remove(self)         self.close() 

on ui have 'start' , 'next' buttons send these messages through socket connection.

i'm creating thread @ 'start' triggers function runs finite loop , calls callback self.on_result in each loop.

this works fine right now. need execute commands @ 2 comments pause , resume thread.

how should achieve ?