The API doesn't support empty inventories.

[KowalskiThomas]

The title says it all.

If I remember well I've already faced twice problems related to the fact you're using, for example

    for x in rgInventory.keys():

Without thinking about the fact rgInventory could be [].

That would be great if you could fix that (since I don't know every where it can happen in the code).

[DrBomb]

Inventories are going to be recoded so I won't be fixing this for now. But if you look at the code here: https://github.com/DrBomb/python-steamcommunity/blob/master/SteamInventory.py#L48
You will see that if a inventory is empty the respective dictionary entry should be an empty dictionary