comment get_real_jid_from_fjid to assure future protection from refactoring...

comment get_real_jid_from_fjid to assure future protection from refactoring and add docstring to get return values without reading the code. Both are importnat for such api funcs

src/common/gajim.py

@@ -127,14 +127,17 @@ def get_room_and_nick_from_fjid(jid):
 	return l
 
 def get_real_jid_from_fjid(account, fjid):
+	'''returns real jid, it returns None
+	if we don't know the real jid'''
 	room_jid, nick = get_room_and_nick_from_fjid(fjid)
-	if not nick: # It's not a fake_jid, so it's not pm
-		return fjid
+	if not nick: # It's not a fake_jid, it is a real jid
+		return fjid # we are mods for example so we know the real jid
 	real_jid = fjid
 	gcs = interface.windows[account]['gc']
 	if gcs.has_key(room_jid):
 		# It's a pm, so if we have real jid it's in contact.jid
 		contact = gc_contacts[account][room_jid][nick]
+		# contact.jid is None when it's not a real jid (we don't know real jid)
 		real_jid = contact.jid
 	return real_jid