Checkbox readout always shows 0

I cannot make the checkbox to give a "1" value when its marked and the button is clicked. I don't know if the problem is within the checkbutton code or I am transferring the data between functions wrong

import tkinter as tk
from tkinter import ttk as ttk


var_koszula1=2

class Aplikacja(tk.Frame):
def __init__(self,  *args, **kwargs):
    tk.Frame.__init__(self,  *args, **kwargs)
    self.grid()
    self.var_koszula1=tk.IntVar(self)        
    tk.Checkbutton(self, text='MARK', variable=var_koszula1).grid()
    print(self.var_koszula1.get())
    tk.Button(self, height=1, width=15, text=("Click"), command= self.create_window_edit).grid()

def create_window_edit(self):
    t = tk.Toplevel(self)
    tk.Label(t, text=("Done")).grid()
    print(self.var_koszula1.get())

root= tk.Tk()
root.title("Szaffa")
app= Aplikacja(root)
root.mainloop()