human
Solve the following python programming problem given the following code:
@ contextmanager 
def _wrap_merge_timestamps(self, broker, calls) : 
    def fake_merge_timestamps(* args, **kwargs) : 
        calls.append (args [0]) 
        orig_merge_timestamps (* args, ** kwargs) 
orig_merge_timestamps = broker.merge_timestamps 
    broker.merge_timestamps = <MASK> 
    try : 
        (yield True) 
finally : 
        broker.merge_timestamps = orig_merge_timestamps 
    
    Given the code above, what is a proper replacement for <MASK>?
assistant
#Here is a proper replacement for <MASK>.
def fake_merge_timestamps(