code: def make_classify_tab(self):
          
          self.pick_frame = tk.Frame(self.tab_classify)
          self.pick_frame2 = tk.Frame(self.tab_classify)
  
          self.solar_class_var = tk.IntVar()
          self.solar_class_var.set(0)  # initialize to unlabeled
          buttonnum = 0
          frame = [self.pick_frame, self.pick_frame2]
          for text, value in self.config.solar_classes:
              b = tk.Radiobutton(frame[buttonnum % 2], text=text,
                                 variable=self.solar_class_var,
                                 value=value, background=self.config.solar_colors[text],
                                 indicatoron=0, width=50, height=2, command=self.change_class)
              b.pack(fill=tk.BOTH, expand=1)
              buttonnum += 1
  
  
          self.pick_frame.grid(row=0, column=0, rowspan=5, sticky=tk.W + tk.E + tk.N + tk.S)
          self.pick_frame2.grid(row=0, column=1, rowspan=5, sticky=tk.W + tk.E + tk.N + tk.S)
  
          undobutton = tk.Button(master=self.tab_classify, text="Undo",
                                 command=self.undobutton_action)
          undobutton.grid(row=6, column=0, columnspan=2, sticky=tk.W + tk.E)
docs: initial set up of classification tab