NP38 披萨店的订单

思路：

step1：使用len()函数判断列表是否为空；

代码如下：

pizza_orders = ['chichen','bacon','durian']
finished_pizza = []
while len(pizza_orders) > 0:
    pizza = pizza_orders.pop()
    print('I made your {} pizza!'.format(pizza))
    finished_pizza.append(pizza)
print(finished_pizza)