Python tkinter pack before

[Layco]

Hi everybody!
Does anyone know what argument the -before parameter of the tkinter pack package manager takes?
I couldn't find an example of it on the Internet, it's missing.
I do not understand: https://www.tcl.tk/man/tcl/TkCmd/pack.html#M9
Thanks!

import tkinter as tk

root = tk.Tk()
root.title('Before example')
root.geometry("300x250")
root.configure(bg='#a8c3bc')

label = tk.Label(root, text="What does before do?", bg="#a8c3bc")
label.pack(before=?????????????????)

button1 = tk.Button(root, text="Clicking", bg="green", fg="white")
button1.pack()

button2 = tk.Button(root, text="Clicking", bg="red", fg="white")
button2.pack()

root.mainloop()