如何暂停一个函数？

root = Tk()

root.title("tkinter + Matplotlib")

root.geometry('700x750')

plt.rcParams['axes.unicode_minus']=False

plt.rcParams['font.sans-serif'] = ['SimHei']

fig = plt.figure()

ax1 = fig.add_subplot(1, 1, 1)

ax2 = ax1.twinx()



ax1.set_title('随机生成数')



ax1.set_ylim()

ax2.set_ylim()



ax1.set_xlim(0, 200)

ax2.set_xlim(0, 200)



ax1.grid(True)



ax1.set_xlabel("time")

ax1.set_ylabel("随机数 1")

ax2.set_ylabel("随机数 2")



canvas = FigureCanvasTkAgg(fig, master=root)

canvas.draw()



canvas.get_tk_widget().pack()



x = 0

ran1 = []

ran2 = []

times = []



def drawImg():



    global ran1

    global ran2

    global times

    global x

    global ax1

    global ax2



    v1 = float(random.randint(-5, 5))

    r1 = float(random.randint(-10, 10))

    ran1.append(v1)

    ran2.append(r1)

    times.append(x)

    x += 1



    ax1.clear()

    ax2.clear()

    ax1.axes.set_ylim(min(ran1)-5, 5+max(ran1))

    ax2.axes.set_ylim(min(ran2)-5, 5+max(ran2))

    ax1.axes.set_xlim(x-200+200, x+20)

    ax2.axes.set_xlim(x-200+20, x+20)



    ax1.plot(times, ran1,'y')

    ax2.plot(times, ran2,'r')

    canvas.draw()

    #global afterHandler

    #afterHandler = root.after(10, drawImg)

    #print(datetime.datetime.now())



def sub_task():

    drawImg()



def task_(time):

    def task__():

        temp = BackgroundScheduler()

        temp.add_job(sub_task,'interval',secOnds= 1,end_date =str(datetime.datetime.now())[:17]+time)

        temp.start()

    return task__



sche_fn = BackgroundScheduler()

sche_fn.add_job(task_('25'),'cron',day_of_week = 'mon-fri',hour = '*',minute = '*',secOnd= '0' )

sche_fn.start()

sche_an = BackgroundScheduler()

sche_an.add_job(task_('55'),'cron',day_of_week = 'mon-fri',hour = '*',minute = '*',secOnd= '30' )

sche_an.start()







def on_closing():

    sche_an.shutdown()

    sche_fn.shutdown()

    #root.after_cancel(afterHandler)

    answer = messagebox.askokcancel("退出", "确定退出吗?")

    if answer:

        plt.close('all')

        root.destroy()

    else:

        root.after(1000, drawImg)





root.protocol("WM_DELETE_WINDOW", on_closing)

root.mainloop()