Seeing how SteamIDs have changed recently, I thought I'd write a Gist to help others (including myself!) decypher how to convert these from one format to the other in Python. First, let's go over basics to convert a 64bit CommunityID into a SteamID:
steamid64ident = 76561197960265728
def commid_to_steamid(commid):
steamid = []
steamid.append('STEAM_0:')
steamidacct = int(commid) - steamid64ident