code: def test_stateful_protocol():
      class StatefulClass:
          def state_dict(self):
              pass
  
          def load_state_dict(self, state_dict):
              pass
  
      assert isinstance(StatefulClass(), _Stateful)
  
      class NotStatefulClass:
          def state_dict(self):
              pass
  
      assert not isinstance(NotStatefulClass(), _Stateful)
  
      class NotStateful2Class:
          def load_state_dict(self, state_dict):
              pass
  
      assert not isinstance(NotStateful2Class(), _Stateful)
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_stateful_protocol() without return types