参考代码:

class Solution:
    def __init__(self, v1, v2):
        self.queue = [v for v in (v1, v2) if v]

    def next(self):
        v = set.queue.pop(0)
        value = v.pop(0)
        if v:
            self.queue.append(v)
        return value

    def hasNext(self):
        return len(self.queue) > 0