def 调用和终止问题

def a1():
        print（"我还会回来的"）
        a=a+1

def a():
            for xunhuan in range(0, 86400):
                    time.sleep(5)
                    print("5秒来一次")

请问如何 在def的for循环里执行def a1的内容，也就是a里没循环一次运行一次a1;
以及如何另外创建一个按钮，可以终止a里的for循环

    import time
    import tkinter as tk
    from threading import Thread

    count = 0
    run = True
    def a1():
        print("我还会回来的")
        global count
        count = count + 1

    def a():
        print("Started...")
        for xunhuan in range(0, 86400):
            global run
            if not run:
                print("Ended!")
                break
            time.sleep(5)
            print("5秒来一次")
            a1()

    def thread_a():
        global run
        run = True
        t = Thread(target=a, args=())
        t.start()
        if not run:
            t.join()


    def stop():
        global run
        run = False
        print("Ending...")

    root = tk.Tk()
    btn1 = tk.Button(root, text="启动", command=thread_a)
    btn1.pack()
    btn2 = tk.Button(root, text="停止", command=stop)
    btn2.pack()
    root.geometry("200x100")
    root.mainloop()

def a1():
        print（"我还会回来的"）
        a=a+1

def a():
            for xunhuan in range(0, 86400):
                    time.sleep(5)
                    print("5秒来一次")
                    a1()

import time
class Test(object):
    def __init__(self,button):
        self.button=button
        self.a=0
    def a0(self):
        print("我还会回来")
        self.a+=1
    def a1(self):
        while self.button==1:
            for xunhuan in range(0, 86400):
                time.sleep(5)
                self.a0()
                print("5秒来一次")

if __name__=='__main__':
    start=1
    test=Test(start)
    test.a1()