human
Solve the following python programming problem given the following code:
def test_trans_id_header_fail(self) : 
    self.assertEqual (self.logger.txn_id, None) 
    def start_response(status, headers, exc_info = None) : 
        self.assertTrue (('X-Trans-Id' in (x [0] for x in headers))) 
app = catch_errors.CatchErrorMiddleware (FakeApp (True), { 
        
}) 
    req = Request.blank ('/v1/a/c/o') 
    app (start_response.environ, start_response) 
    self.assertEqual (len (self.logger.txn_id), 34) 

    
    

    Fix the buggy line: app (start_response.environ, start_response)
assistant
#Here is Python code to fix the buggy line: app (start_response.

app (req.environ, start_response)