How to subclass Python list without type problems?
Firstly, I recommend you follow Björn Pollex’s advice (+1). To get past this particular problem (type(l2 + l3) == CustomList), you need to implement a custom __add__(): def __add__(self, rhs): return CustomList(list.__add__(self, rhs)) And for extended slicing: def __getitem__(self, item): result = list.__getitem__(self, item) try: return CustomList(result) except TypeError: return result I also recommend… pydoc … Read more