human
Solve the following python programming problem given the following code:
def _set_consumer_versions_callback(self, cached_tracker) : 
    def consumer_versions(rct) : 
        rct.set_versions (CONSUMER_1, { 
            TEST_RESOURCE_TYPE : TEST_VERSION_A, 
}) 
cached_tracker.set_consumer_versions_callback (<MASK>) 
    
    Given the code above, what is a proper replacement for <MASK>? Choose among: cached_tracker, self
assistant
#Here is a proper replacement for <MASK>.
def consumer_versions(