How to replace the icon in a Tkinter app?

I am using Python 3.5.0 on Windows 10 and want to replace this:

To change the icon you should use iconbitmap or wm_iconbitmap I'm under the impression that the file you wish to change it to must be an ico file.

import tkinter as tk

root = tk.Tk()
root.iconbitmap("myIcon.ico")