old_contents: from unittest.mock import Mock
  
  from jupyterhub import orm
  from remoteappmanager.services.reverse_proxy import ReverseProxy
  from tornado import gen, testing
  
  
  class TestReverseProxy(testing.AsyncTestCase):
      @testing.gen_test
      def test_reverse_proxy_operations(self):
          coroutine_out = None
  
          @gen.coroutine
          def mock_api_request(self, *args, **kwargs):
              nonlocal coroutine_out
              yield gen.sleep(0.1)
              coroutine_out = dict(args=args, kwargs=kwargs)
  
          reverse_proxy = ReverseProxy("http://fake/api", "token")
          reverse_proxy._reverse_proxy = Mock(spec=orm.Proxy)
          reverse_proxy._reverse_proxy.api_request = mock_api_request
  
          yield reverse_proxy.register("/hello/from/me/",
                                       "http://localhost:12312/")
  
          self.assertEqual(coroutine_out["kwargs"]["method"], "POST")
  
          yield reverse_proxy.unregister("/hello/from/me/")
  
          self.assertEqual(coroutine_out["kwargs"]["method"], "DELETE")
  
new_contents: from unittest.mock import Mock
  
  from jupyterhub import orm
  from remoteappmanager.services.reverse_proxy import ReverseProxy
  from tornado import gen, testing
  
  
  class TestReverseProxy(testing.AsyncTestCase):
      @testing.gen_test
      def test_reverse_proxy_operations(self):
          coroutine_out = None
  
          @gen.coroutine
          def mock_api_request(self, *args, **kwargs):
              nonlocal coroutine_out
              yield gen.sleep(0.1)
              coroutine_out = dict(args=args, kwargs=kwargs)
  
          reverse_proxy = ReverseProxy(
              endpoint_url="http://fake/api",
              auth_token="token")
          reverse_proxy._reverse_proxy = Mock(spec=orm.Proxy)
          reverse_proxy._reverse_proxy.api_request = mock_api_request
  
          yield reverse_proxy.register("/hello/from/me/",
                                       "http://localhost:12312/")
  
          self.assertEqual(coroutine_out["kwargs"]["method"], "POST")
  
          yield reverse_proxy.unregister("/hello/from/me/")
  
          self.assertEqual(coroutine_out["kwargs"]["method"], "DELETE")
  
subject: Solve deprecation warning from Traitlets