modeling wallets

During my implementation of a proof of concept for virtual wallets, ive
been trying to lock down the concept of wallet.

I've come up with:

"A wallet is a container of money"

I dont distinguish between single user and multi user wallets, because, in
the digital sense, it's the same code.

So what I have is:

#user   namespace : wallet  <URI>

The URI of the wallet then can contain pointers to all the relevant
details, e.g. where to find APIs, the name, where to send transactions.
Then the URI is of type "Wallet".

It seems like quite a simple model, another alternative would be to say
"hasWallet", but that seemed a little ugly to me.

Thoughts?