I would like to achieve in Python the following semantics which is present in Kotlin: myset = set() for elem in arr: if not myset.add(elem): return 'duplicate found'  I am looking for a way to get a slight performance boost by 'hijacking' add-to-set operation by analysing the returned value. It should be better if compared to the following approach I already know in Python: myset = set() for elem in arr: if elem in myset: return 'duplicate found' myset.add(elem)  Yet as far as I can observe add() method of set returns None no matter what the outcome of adding is. Is there such a method in Python3? Looking into the documentation I have not managed to find such a result returning add-to-set method yet.
No, and it has been rejected.