Python GUI server pinging app

ping.py

import tkinter, os
window = tkinter.Tk()
def callbk():
    _res = os.system('ping -c 1 ' + ent.get())
    res.configure(text='success' if _res == 0 else 'fail')
lbl = tkinter.Label(window, text='IP: ')
ent = tkinter.Entry(window)
btn = tkinter.Button(window, text='ping', command=callbk)
res = tkinter.Label(window, text='...')
lbl.pack()
ent.pack()
btn.pack()
res.pack()
window.mainloop()