Tranformer un script en module

from tkinter import *
__name__="screenResDef"
reswidth=None
resheight=None
# Définition de la résolution de l'écran
def scnres1():
    reswidth=800
    resheight=600
    tk.destroy()
def scnres2():
    reswidth=1024
    resheight=768
    tk.destroy()
def scnres3():
    reswidth=1152
    resheight=864
    tk.destroy()
def scnres4():
    reswidth=1280
    resheight=720
    tk.destroy()
def scnres5():
    reswidth=1280
    resheight=960
    tk.destroy()
def scnres6():
    reswidth=1280
    resheight=1024
    tk.destroy()
def scnres7():
    reswidth=1360
    resheight=768
    tk.destroy()
def scnres8():
    reswidth=1366
    resheight=768
    tk.destroy()
def scnres9():
    reswidth=1600
    resheight=900
    tk.destroy()
def scnres10():
    reswidth=1920
    resheight=1080
    tk.destroy()
def screenResolution():
    tk=Tk("Résolution de l'écran")
    cvs=Canvas(tk, width=500, height=250)
    tk.resizable(0,0)
    cvs.pack()
    cvs.create_text(250, 50, text="The Legend of Zelda : Oracle of Seasons/Ages", font=("Zelda Oracles", 15))
    cvs.create_text(250, 150, text="Choisissez la resolution de votre ecran", font=("Zelda Oracles", 15))
    btn=Button(tk, text="800x600", command=scnres1)
    btn2=Button(tk, text="1024x768", command=scnres2)
    btn3=Button(tk, text="1152x864", command=scnres3)
    btn4=Button(tk, text="1280x720", command=scnres4)
    btn5=Button(tk, text="1280x960", command=scnres5)
    btn6=Button(tk, text="1280x1024", command=scnres6)
    btn7=Button(tk, text="1360x768", command=scnres7)
    btn8=Button(tk, text="1366x768", command=scnres8)
    btn9=Button(tk, text="1600x900", command=scnres9)
    btn10=Button(tk, text="1920x1080", command=scnres10)
    btn.pack()
    btn2.pack()
    btn3.pack()
    btn4.pack()
    btn5.pack()
    btn6.pack()
    btn7.pack()
    btn8.pack()
    btn9.pack()
    btn10.pack()