title: Tk Python combobox in loop get the data selected
body: <p>I want to show in a loop a dropdown list and capture the data selected. I have the below code, but even printing it is not working.. Could someone help me please?</p>
  <p>So let's say that on the 1st screen I chose a, b, c in that order, then on the 2nd I chose d, c, a in that order; and on the last I chose a, d, c in that order, I would like my final list to be:</p>
  <pre><code>lb_sel = [['a', 'b', 'c'],['d', 'c', 'a'],['a', 'd', 'c']]
  
  from tkinter import filedialog, messagebox, ttk, constants
  from tkinter import *
  
  
  def DropDown(argslist,index):
      var = StringVar()
      c= ttk.Combobox(root,width=40)
      c['values'] = argslist
      c.textvariable=var
      c.current(0)
      c.bind(&quot;&lt;&lt;ComboboxSelected&gt;&gt;&quot;,choice_sel)
      c.grid(row=index-1, column=1,padx=(15,25))
      c.index=index
  
  nb_choice = 3
  has_choice = True
  lst = ['a', 'b', 'c', 'd']
  lb_sel = [[] for i in range(nb_choice)]
  
  lst.insert(0,'Select a choice')
  for i in range(nb_choice):
      root = Tk()
      root.focus_force()
      root.title('Choices')
      labl1 = ttk.Label(text = 'Select the first choice of N.' + str(i+1))
      labl1.grid(row = 0, column = 0)
      labl2 = ttk.Label(text = 'Select the second choice of N.' + str(i+1))
      labl2.grid(row = 1, column = 0)
      labl3 = ttk.Label(text = 'Select the third choice of N.' + str(i+1))
      labl3.grid(row = 2, column = 0)
      def choice_sel():
          print(lb1.get())
      lb1 = DropDown(lst,1)
      lb2 = DropDown(lst,2)
      lb3 = DropDown(lst,3)
      
      exit_but = Button(root, text = 'OK', command = lambda: choice_sel, height = 3, width = 5)
      exit_but.grid(row = 2, column = 2)
      root.mainloop()
  </code></pre>