#!/usr/bin/env python3# Completed implementation of a queue ADTclass Queue:    def __init__(self):        self.items = []    def is_empty(self):        return self.items == []    def enqueue(self, item):        self.items.insert(0, item)    def dequeue(self):        return self.items.pop()    def size(self):        return len(self.items)if __name__ == "__main__":    q = Queue()    q.enqueue("hello")    q.enqueue("dog")    q.enqueue(3)    print(q.dequeue())