[Snippet - useful class]

list_subtraction.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-


class MyList(list):
    def __init__(self, *args):
        super(MyList, self).__init__(args)

    def __sub__(self, other):
        return self.__class__(*[item for item in self if item not in other])


if __name__ == "__main__":
    # practice 1
    x = MyList(1, 2, 3, 4)
    y = MyList(2, 5, 2)
    z = x - y
    assert z == [1, 3, 4], "assertion failed"

    # practice 2
    x = [1, 2, 3, 4]
    y = [2, 5, 2]
    z = MyList(*x) - MyList(*y)
    assert z == [1, 3, 4], "assertion failed"