python tkinter toplevel always on top code example

Example 1: tkinter always on top

app.attributes('-topmost', True)
app.update()

Example 2: tkinter toplevel

from tkinter import *

root = Tk()
l1 = Label(root, text="Main Window Label")
l1.pack()

top = Toplevel()
l2 = Label(top, text="Toplevel Window Label")
l2.pack()
top.mainloop()
root.mainloop()