how to pack a widget in on the left in tkinter code example

Example 1: pack tkinter

from Tkinter import *

root = Tk()

listbox = Listbox(root)
listbox.pack(fill=BOTH, expand=1)

for i in range(20):
    listbox.insert(END, str(i))

mainloop()

Example 2: pack() tkinter

Label().pack()