import random
class Printer:
# 打印机类
def __init__(self, ppm):
self.pagerate = ppm # 打印速度
self.currentTask = None # 当前打印任务
self.timeRemaining = 0 # 任务倒计时:当前任务还差几秒钟打印完
def tick(self): # 打印一秒
if self.currentTask != None: # 若当前有打印任务,任务倒