Checkbutton tkinter onvalue

checkbutton tkinter example

c1 = tk.Checkbutton(window, text='Python',variable=var1, onvalue=1, offvalue=0, command=print_selection)
c1.pack()
c2 = tk.Checkbutton(window, text='C++',variable=var2, onvalue=1, offvalue=0, command=print_selection)
c2.pack()