> for example, an innocent board[pos] access will look up __getitem__ in board.__dict__ and call the result Pedantic note: Special methods aren't looked up in

> for example, an innocent board[pos] access will look up __getitem__ in board.__dict__ and call the result Pedantic note: Special methods aren't looked up in __dict__, they're members of the C struct describing the type. "board[pos]" will look up the type of board, then call the tp_getitem function pointer in that struct. That can be a bit surprising to people: class A: def __getitem__(self, key): print("A.__getitem__({})".format(key)) def foo(self, x): print("A.foo({})".format(x)) a = A() a["special"] a.foo("ordinary") a.__getitem__ = lambda key: print("Overriden __getitem__({})".format(key)) a.foo = lambda x: print("Overriden foo({})".format(x)) a["special"] a.foo("ordinary") Outputs: A.__getitem__(special) A.foo(ordinary) A.__getitem__(special) Overriden foo(ordinary)