human
Solve the following python programming problem given the following code:
def test_no_instance_passthrough_404(self) : 
    def fake_compute_get(* args, **kwargs) : 
        raise exception.InstanceNotFound (instance_id = 'fake') 
self.stubs.Set (compute.api.API, 'get', <MASK>) 
    url = '/v2/fake/servers/70f6db34-de8d-4fbd-aafb-4065bdfa6115' 
    res = self._make_request (url) 
    self.assertEqual (res.status_int, 404) 
    
    Given the code above, what is a proper replacement for <MASK>?
assistant
#Here is a proper replacement for <MASK>.
def fake_compute_get(