json.dump unable to serialize a dictionary containing a list in python

I have this part `[{'scenariotestinputid': 1, 'scenarioid_id': 1, 'testinputid_id': 1}]` inside a python dictionary called result. When I call json.dumps(result), I get a TypeError saying that [{'scenariotestinputid': 1, 'scenarioid_id': 1, 'testinputid_id': 1}] is not JSON serializable. Can anyone explain why? Edit1: The complete "result" dictionary content is: ``` result: {'scenarios': [{'inputs': [{'scenariotestinputid': 1, 'scenarioid_ id': 1, 'testinputid_id': 1}], 'scenarioid': 1, 'scenarioname': u'Default Scenario', 'testid_id': 1, 'isdefault': 1}, {'inputs': [], 'scenarioid': 2, 'scenarioname': u'Scenario-1', 'testid_id': 1, 'isdefault': 0}], 'status': 'success'} ``` The code I'm using is: ``` if x == y: scenarios_list = Scenario.objects.filter(testid=testcase).order_by("scenarioname") scenarios_dict_list = [] for scenario in scenarios_list: scenario_inputs = scenario.scenariotestinput_set.values() scenario_dict = scenario.__dict__ del scenario_dict['_state'] scenario_dict['inputs'] = scenario_inputs scenarios_dict_list.append(scenario_dict) result['scenarios'] = scenarios_dict_list result['status'] = "success" return HttpResponse(json.dumps(result), content_type="application/json") ``` inside a function Edit2: The traceback is as follows: ``` (Pdb) > /opt/my_apps/cpr_proj/cpr/views.py(512)set_benchmark_metrics_dispatcher() -> return HttpResponse(json.dumps(result), content_type="application/json") (Pdb) TypeError: TypeErro...izable",) > /opt/my_apps/cpr_proj/cpr/views.py(512)set_benchmark_metrics_dispatcher() -> return HttpResponse(json.dumps(result), content_type="application/json") (Pdb) bt /opt/Python-2.7.3/Lib/threading.py(524)__bootstrap() -> self.__bootstrap_inner() /opt/Python-2.7.3/Lib/threading.py(551)__bootstrap_inner() -> self.run() /opt/Python-2.7.3/Lib/threading.py(504)run() -> self.__target(*self.__args, **self.__kwargs) /opt/Python-2.7.3/Lib/SocketServer.py(582)process_request_thread() -> self.finish_request(request, client_address) /opt/Python-2.7.3/Lib/SocketServer.py(323)finish_request() -> self.RequestHandlerClass(request, client_address, self) /usr/local/lib/python2.7/site-packages/django/core/servers/basehttp.py(139)__init__() -> super(WSGIRequestHandler, self).__init__(*args, **kwargs) /opt/Python-2.7.3/Lib/SocketServer.py(638)__init__() -> self.handle() /opt/Python-2.7.3/Lib/wsgiref/simple_server.py(124)handle() -> handler.run(self.server.get_app()) /opt/Python-2.7.3/Lib/wsgiref/handlers.py(85)run() -> self.result = application(self.environ, self.start_response) /usr/local/lib/python2.7/site-packages/django/contrib/staticfiles/handlers.py(67)__call__() -> return self.application(environ, start_response) /usr/local/lib/python2.7/site-packages/django/core/handlers/wsgi.py(241)__call__() -> response = self.get_response(request) /usr/local/lib/python2.7/site-packages/django/core/handlers/base.py(111)get_response() -> response = callback(request, *callback_args, **callback_kwargs) > /opt/my_apps/cpr_proj/cpr/views.py(512)set_benchmark_metrics_dispatcher() -> return HttpResponse(json.dumps(result), content_type="application/json") /opt/Python-2.7.3/Lib/json/__init__.py(231)dumps() -> return _default_encoder.encode(obj) /opt/Python-2.7.3/Lib/json/encoder.py(201)encode() -> chunks = self.iterencode(o, _one_shot=True) /opt/Python-2.7.3/Lib/json/encoder.py(264)iterencode() -> return _iterencode(o, 0) /opt/Python-2.7.3/Lib/json/encoder.py(178)default() -> raise TypeError(repr(o) + " is not JSON serializable") ```