class MyList(list):
    def __mul__(self, other):
        if isinstance(other, MyList):
            return MyList((x,y) for x in self for y in other)
        else:
            return super().__mul__(self, other)

a = MyList([1, 2, 3])
b = MyList([4, 5, 6, 7])
print(a*b)