human
Solve the following python programming problem given the following code:
@ mock.patch ('oauth2client.contrib.django_util.views.pickle') 
def test_callback_handles_bad_flow_exchange(self, pickle) : 
    request = self.factory.get ('oauth2/oauth2callback', data = { 
        'state' : json.dumps (self.fake_state), 
        'code' : 123, 
}) 
    self.session ['google_oauth2_csrf_token'] = self.CSRF_TOKEN 
    flow = OAuth2WebServerFlow (client_id = 'clientid', client_secret = 'clientsecret', scope = ['email'], state = json.dumps (self.fake_state), redirect_uri = request.build_absolute_uri ('oauth2/oauth2callback')) 
    self.session ['google_oauth2_flow_{0}'.format (self.CSRF_TOKEN)] = pickle.dumps (flow) 
    def local_throws(code) : 
        raise FlowExchangeError ('test') 
flow.step2_exchange = local_throws 
    pickle.loads.return_value = response 
    request.session = self.session 
    response = views.oauth2_callback (request) 
    self.assertTrue (isinstance (response, http.HttpResponseBadRequest)) 

    
    

    Fix the buggy line: pickle.loads.return_value = response
assistant
#Here is Python code to fix the buggy line: pickle.

pickle.loads.return_value = flow