old_contents: # coding: utf-8
  # 参考 http://meganezumi.seesaa.net / article / 391262919.html
  
  import tkinter as Tk
  import time
  import datetime
  
  my_time = (datetime.datetime(2069, 1, 28) -
             datetime.datetime.now()).total_seconds()
  
  WIDTH = 10
  
  
  class Timer(Tk.Frame):
  
      def __init__(self, master=None):  # 各ボタンの配置
          Tk.Frame.__init__(self, master)
  
          self.master.title('I have only 1600000000 seconds till my death')
  
          b1 = Tk.Button(self, text=u'start', command=self.start,
                         font='Helvetica, 12')
          b2 = Tk.Button(self, text=u'reset', command=self.stop,
                         font='Helvetica, 12')
          self.tokei = Tk.Label(self, text=my_time, font='Helvetica, 25')
  
          self.s1 = Tk.Spinbox(self, from_=0, to=99, increment=1, width=WIDTH)
          self.s2 = Tk.Spinbox(self, from_=0, to=59, increment=1, width=WIDTH)
  
          b1.grid(row=1, column=0, columnspan=2,
                  padx=5, pady=2, sticky=Tk.W + Tk.E)
          b2.grid(row=1, column=2, columnspan=2,
                  padx=5, pady=2, sticky=Tk.W + Tk.E)
          self.tokei.grid(row=2, column=0, columnspan=4,
                          padx=5, pady=2, sticky=Tk.W + Tk.E)
  
      def start(self):  # Startを押したときの動作 ほんとは押さなくてもカウントが始まってくれて良いのだが
          self.started = True
          self.finish = time.time() + int(my_time)
          self.count()
  
      def count(self):
          if self.started:
              t = self.finish - time.time()
              self.tokei.config(text="%02d" % t)  # 表示時間を1秒毎に書き換え
              self.after(100, self.count)
  
      def stop(self):  # 停止処理
          self.started = False
          self.tokei.config(text=my_time)
  
  if __name__ == '__main__':  # スクリプトファイルとして実行されたとき用
      f = Timer()
      f.pack()
      f.mainloop()
  
new_contents: # coding: utf-8
  # 参考 http://meganezumi.seesaa.net / article / 391262919.html
  
  import tkinter as Tk
  import time
  import datetime
  
  # 寿命を残り20年，54歳までとする
  my_time = (datetime.datetime(2039, 1, 28) -
             datetime.datetime.now()).total_seconds()
  
  WIDTH = 10
  
  
  class Timer(Tk.Frame):
  
      def __init__(self, master=None):  # 各ボタンの配置
          Tk.Frame.__init__(self, master)
  
          self.master.title('I have only 1600000000 seconds till my death')
  
          b1 = Tk.Button(self, text=u'start', command=self.start,
                         font='Helvetica, 12')
          b2 = Tk.Button(self, text=u'reset', command=self.stop,
                         font='Helvetica, 12')
          self.tokei = Tk.Label(self, text=my_time, font='Helvetica, 25')
  
          self.s1 = Tk.Spinbox(self, from_=0, to=99, increment=1, width=WIDTH)
          self.s2 = Tk.Spinbox(self, from_=0, to=59, increment=1, width=WIDTH)
  
          b1.grid(row=1, column=0, columnspan=2,
                  padx=5, pady=2, sticky=Tk.W + Tk.E)
          b2.grid(row=1, column=2, columnspan=2,
                  padx=5, pady=2, sticky=Tk.W + Tk.E)
          self.tokei.grid(row=2, column=0, columnspan=4,
                          padx=5, pady=2, sticky=Tk.W + Tk.E)
  
      def start(self):  # Startを押したときの動作 ほんとは押さなくてもカウントが始まってくれて良いのだが
          self.started = True
          self.finish = time.time() + int(my_time)
          self.count()
  
      def count(self):
          if self.started:
              t = self.finish - time.time()
              self.tokei.config(text="%02d" % t)  # 表示時間を1秒毎に書き換え
              self.after(100, self.count)
  
      def stop(self):  # 停止処理
          self.started = False
          self.tokei.config(text=my_time)
  
  if __name__ == '__main__':  # スクリプトファイルとして実行されたとき用
      f = Timer()
      f.pack()
      f.mainloop()
  
subject: Update till_my_death.py