# test containment operator on subclass of a native type class mylist(list): pass class mydict(dict): pass class mybytes(bytes): pass l = mylist([1, 2, 3]) print(0 in l) print(1 in l) d = mydict({1:1, 2:2}) print(0 in l) print(1 in l) b = mybytes(b'1234') print(0 in b) print(b'1' in b)