os.path.exists() and Samba shares

[BDZ]

Hello. I have written a Python 3.1 script running on Windows that uses
os.path.exists() to connect to network shares. If the various network
shares require different user account and password combos than the
account the script is running under the routine returns false. I need
something like os.samba.path.exists(username,password,path). Does
anyone have a suggestion on how I can accomplish what I need to do in
Python?