Checkbuttons on every notebook tabs Tkinter Python

On every Tkinter notebook tab, there is a list of checkbuttons and the variables get saved to their corresponding v[ ] (i.e. cb.append(Checkbuttons(.., variables = v[x],..)).

For now, I am encountering this error:

File "/home/pass/OptionsInterface.py", line 27, in __init__
self.ntbk_render(f = self.f1, ntbkLabel="Options",cb = optsCb, msg = optMsg)
File "/home/pass/OptionsInterface.py", line 59, in ntbk_render
text = msg[x][1], command = self.cb_check(v, opt)))
File "/home/pass/OptionsInterface.py", line 46, in cb_check
opt[ix]=(v[ix].get())
IndexError: list assignment index out of range

And I think the error is coming here. I don't know how to access the values of the checkbutton variables.

def cb_check(self, v = [], cb = [], opt = []):
    for ix in range(len(cb)):
      opt[ix]=(v[ix].get())
    print opt

Here are some snippets:

     self.ntbk = ttk.Notebook(self.master)

    self.f1 = ttk.Frame(self.ntbk)
    self.f2 = ttk.Frame(self.ntbk)
    self.f3 = ttk.Frame(self.ntbk)
    self.f4 = ttk.Frame(self.ntbk)
    self.rowTracker = 0

    self.ntbk.add(self.f1, text = "Tab1")
    self.ntbk.add(self.f2, text = "Tab2")
    self.ntbk.add(self.f3, text = "Tab3")
    self.ntbk.add(self.f4, text = "Tab4")
    self.ntbk.grid()
    optMsg, pluginMsg, classifierMsg, logMsg = [], [], [], []
    optsCb, pluginCb, classCb, logCb = [],[],[],[]

    self.ntbk_render(f = self.f1, ntbkLabel="Options",cb = optsCb, msg = optMsg)
    self.ntbk_render(f = self.f2, ntbkLabel="Plugins",cb = pluginCb, msg = pluginMsg)
    self.ntbk_render(f = self.f3, ntbkLabel="Classifiers",cb = classCb, msg = classifierMsg)
    self.ntbk_render(f = self.f4, ntbkLabel="Logging",cb = logCb, msg = logMsg)

    self.btn = Button(master, text="Ok", command = self.closeWindow)
    self.btn.grid(row = self.rowTracker+1, sticky = "se")
    self.master.grid()

  def cb_check(self, v = [], cb = [], opt = []):
    for ix in range(len(cb)):
      opt[ix]=(v[ix].get())
    print opt

  def ntbk_render(self, f=None, ntbkLabel="", cb = [], msg = []):
    v = []
    opt = []
    msg = get_thug_args(word = ntbkLabel, argList = msg) #Allows to get the equivalent list (2d array) 
      #to serve as texts for their corresponding checkboxes

    for x in range(len(msg)):
      v.append(IntVar())
      off_value = 0
      on_value = 1
      cb.append(Checkbutton(f, variable = v[x], onvalue = on_value, offvalue = off_value,
        text = msg[x][1], command = self.cb_check(v, opt)))
      cb[x].grid(row=self.rowTracker + x, column=0, sticky='w')
      opt.append(off_value)
      cb[-1].deselect()

After solving the error, I want to get all the values of the checkbutton variables of each tab after pressing the button Ok at the bottom. Any tips on how to do it will help!