class PhotoPool:
    pool = []
    @classmethod
    def get(cls):
        return cls.pool
    @classmethod
    def add(cls, val):
        if len(cls.pool) >= 6:
            cls.pool.remove(cls.pool[0])
        cls.pool.append(val)
    @classmethod
    def remove(cls, key):
        cls.pool.pop(key)