Simple digital clock using Tkinter in Python 3

import sys
from tkinter import *
import time
def tick():
    time_string = time.strftime("%H:%M:%S")
    clock.config(text=time_string)
    clock.after(200, tick)

root = Tk()
clock=Label(root, font=("times", 100, "bold"), bg= "white")
clock.grid(row=0, column=1)
tick()

root.mainloop()