Python – Executing Windows administrative shell commands on Windows using Python

I have a batch script using Windows shell commands to perform several administrative actions.
The script is running great on Windows 7 but when i try launching it from Python 2.6 nothing happens:

import os
a = os.popen("somebatchfile.bat")

I assume that this is because the bat file uses several commands that require an administrative privileges but i don't want to prompt to a password using runas.exe or embedding the password within the code.

Is there any way to make UAC prompt for user approval or something?