human
Solve the following python programming problem given the following code:
def _patch_thread_ident(self) : 
    self.ident = 1 
    test_instance = test_instance 
    class MockThreadingLocal (object) : 
        def __init__(self) : 
            self.__dict__ ['state'] = collections.defaultdict (dict) 
def __deepcopy__(self, memo) : 
            return self 
def __getattr__(self, key) : 
            ns = self.state [test_instance.ident] 
            try : 
                return ns [key] 
except KeyError : 
                raise AttributeError (key) 
def __setattr__(self, key, value) : 
            ns = self.state [test_instance.ident] 
            ns [key] = value 
def __delattr__(self, key) : 
            ns = self.state [test_instance.ident] 
            try : 
                del ns [key] 
except KeyError : 
                raise AttributeError (key) 
return mock.patch.object (enginefacade, '_TransactionContextTLocal', MockThreadingLocal) 

    
    

    Fix the buggy line: test_instance = test_instance
assistant
#Here is Python program to fix the buggy line: test_instance = test_instance
.

test_instance = self