class Perk:
    def __init__(self, key):
        self.key = key

    def __hash__(self):
        return hash(self.key)

    def __eq__(self, other):
        return self.key == other.key


class Bag:
    def __init__(self, items):
        self.items = items

    def __iter__(self):
        return iter(self.items)

    def __getitem__(self, i):
        return self.items[i]

    def __contains__(self, x):
        return x in self.items


table = {}
table[Perk("a")] = 1
table[Perk("a")] = 2
result_size = len(table)
result_value = table[Perk("a")]
bag = Bag([3, 4, 5])
result_loop = [x * 2 for x in bag]
result_item = bag[1]
result_in = 4 in bag
result_out = 9 in bag