Tkinter don't get ver from file via pickle

[Gribouillis]

The problem comes from using global variables s1, s2, s2. Try this version

import os
import tkinter as tk
import pickle
 
s = [0, 0, 0]
 
class Cbuttons:
   def __init__(self):
       self.root = tk.Tk()
       self.root.title("Checklist")
       self.checkvars = [tk.IntVar() for i in range(3)]
       self.main()
 
 
   def save(self):
     print('To save:', *s)
     with open('asy.txt', 'wb') as f:
       pickle.dump(s, f)
       print('Saved:', *s)
 
   def loading(self):
     if not os.path.exists('asy.txt'):
         with open('asy.txt', 'wb') as f:
             pickle.dump(s, f)
     with open('asy.txt', 'rb') as f:
       s[:] = pickle.load(f)
       for v, n in zip(self.checkvars, s):
           v.set(n)
       print('Loaded:', *s)
 
   def confirm(self):
       s[:] = [1 if v.get() else 0 for v in self.checkvars]
       print('chek status:', *s)
       self.save()
  
   def main(self):
       C1 = tk.Checkbutton(
           self.root, text="Option A",
           variable=self.checkvars[0], anchor='w', onvalue=1,
                           offvalue=0, height=1, width=40, command=self.confirm)
       C2 = tk.Checkbutton(
           self.root, text="Option B",
           variable=self.checkvars[1], anchor='w', onvalue=1,
                           offvalue=0, height=1, width=40, command=self.confirm)
       C3 = tk.Checkbutton(
           self.root, text="Option C",
           variable=self.checkvars[2], anchor='w', onvalue=1,
                           offvalue=0, height=1, width=40, command=self.confirm)
       C1.pack()
       C2.pack()
       C3.pack()
       b = tk.Button(self.root, text="OK", command=self.loading)
       b.pack()
 
       self.root.mainloop()
  
  
if __name__ == '__main__':
   Cbuttons()