human
Solve the following python programming problem given the following code:
def _get_tenant_usages(self, detailed = '') : 
    req = fakes.HTTPRequest.blank (('?detailed=%s&start=%s&end=%s' % (detailed, START.isoformat (), STOP.isoformat ()))) 
    req.environ ['nova.context'] = self.admin_context 
    orig_get_active_by_window_joined = objects.InstanceList.get_active_by_window_joined 
    def fake_get_active_by_window_joined(context, begin, end = None, project_id = None, host = None, expected_attrs = None, use_slave = False) : 
        self.assertEqual (['flavor'], expected_attrs) 
        return orig_get_active_by_window_joined (context, begin, end, project_id, host, expected_attrs, use_slave) 
with mock.patch.object (objects.InstanceList, 'get_active_by_window_joined', side_effect = fake_get_active_by_window_joined) : 
        res_dict = self.controller.index (self) 
        return res_dict ['tenant_usages'] 

    
    

    Fix the buggy line: res_dict = self.controller.index (self)
assistant
#Here is Python code to fix the buggy line: res_dict = self.

res_dict = self.controller.index (req)