human
Solve the following python programming problem given the following code:
def _to_set(source, set_type) : 
    def subscribe(observer) : 
        s = set_type () 
        def on_completed() : 
            observer.on_next (s) 
            observer.on_completed () 
return source.subscribe (s.add, observer.on_error, on_completed) 
return AnonymousObservable (source) 

    
    

    Fix the buggy line: return AnonymousObservable (source)
assistant
#Here is Python program to fix the buggy line: return AnonymousObservable (source)
.

return AnonymousObservable (subscribe)