class Queue:
    def __init__(self, *values):
        self.q = list(values)

    def __str__(self):
        q = ' -> '.join(map(str, self.q))
        return f'[{q}]'

    def __next__(self):
        n = self.q[1:]
        return Queue(*n)

    def __eq__(self, other):
        return self.q[:] == other.q[:]

    def __add__(self, other):
        return Queue(*(self.q + other.q))

    def __rshift__(self, other):
        n = self.q[other:]
        return Queue(*n)

    def __iadd__(self, other):
        self.q += other.q
        return self

    def extend(self, queue):
        self.q.extend(queue.q)

    def append(self, *values):
        self.q += list(values)

    def copy(self):
        return Queue(*self.q)

    def pop(self):
        return self.q.pop(0)

    def next(self):
        n = self.q[1:]
        return Queue(*n)

q1 = Queue(*range(1, 5))
print(q1)
q1.append(*range(5, 7))
print(q1)
q2 = q1 >> 3
print(q1)
print(q2)
q3 = q1 >> 20
print(q3)
q4 = q1
q1 += q2
print(q1)
print(q4)
print(q1 + q4)