Display a popup message box

A pop-up message box can be invoked using the following script:

import ctypes 
from System.Windows.Media import Brushes

MB_OK = 0x0
MB_OKCXL = 0x01
MB_YESNOCXL = 0x03
MB_YESNO = 0x04
MB_HELP = 0x4000
ICON_EXLAIM=0x30
ICON_INFO = 0x40
ICON_STOP = 0x10

def Button1_Click(sender, e):

ctypes.windll.user32.MessageBoxW(0, "Message text", "Pop-up header", MB_YESNO | ICON_EXLAIM)

Button1.Click += Button1_Click