import tkinter
main = tkinter.Tk()
lis = ["System", "Linux", "Python", "Tkinter"]
ran = tkinter.Listbox(main, selectmode = 'single', height = 3)
for i in lis :
   ran.insert(END, i)
   ran.pack()
main.mainloop()

import tkinter
main = tkinter.Tk()
lis = ["System", "Linux", "Python", "Tkinter"]
run = tkinter.Listbox(main, selectmode='single', height=3)
run.pack()
for i in lis:
   run.insert(tkinter.END, i)
main.mainloop()