You can focus to another dummy widget.
Edit
from Tkinter import *
def callback():
print master.focus()
master = Tk()
e = Entry(master)
e.pack()
e.focus()
b = Button(master, text="get", width=10, command=callback)
b.pack()
master.mainloop()
Focusing on a non-'focusable' widget will remove focus from another widget.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…