title: Python Tkinter Notebook with Checkbuttons
body: <p>I'm having difficulties resolving checkbutton issue in tkinter. I'm trying to modify code found here on stackoverflow from another question. My issue is that my check buttons start off as "square checked" when I want them to have a value of 0, thus being unchecked. My second issue is that they uncheck and check together, you cant check 1 and have the other unchecked.</p>
  
  <pre><code>import sys
  import math
  from tkinter import ttk
  import tkinter
  
  root = tkinter.Tk()
  note = ttk.Notebook(root)
  
  OnOrOff1 = 0
  OnOrOff2 = 0
  
  tab1 = ttk.Frame(note)
  tab2 = ttk.Frame(note)
  tab3 = ttk.Frame(note)
  
  Check1 = ttk.Checkbutton(tab1, variable=OnOrOff1, onvalue=1, offvalue=0, text="Check me")
  Check1.grid(row=1,column=1,sticky="W")
  Check2 = ttk.Checkbutton(tab1, variable=OnOrOff2, onvalue=1, offvalue=0, text="Check me")
  Check2.grid(row=2,column=1,sticky="W")
  
  note.add(tab1, text = "Tab One")
  note.add(tab2, text = "Tab Two")
  note.add(tab3, text = "Tab Three")
  note.grid()
  root.mainloop()
  exit()
  </code></pre>
  
  <p>Thanks</p>