How Do I Update This Text Box's Text In Tkinter?

So I am making a stopwatch in python with tkinter, I have the loop for updating the time working, but I have it so the loop clears the text box, and then updates the text box with

Solution 1:

Add:

screen.delete("1.0", END)

Before you do:

screen.insert(END, stop_time)

This will clear all the text from the text box. Effbot has more information if your interested. This will produce something similar to: