Function snip1155_reference_impl::state::balances_w

pub fn balances_w<'a>(
    storage: &'a mut dyn Storage,
    token_id: &str
) -> Bucket<'a, Uint128>

Multilevel bucket to store balances for each token_id & addr combination. Key is to be [token_id, owner: to_binary(&Addr)?.as_slice()]
When using balances_w make sure to also check if need to change current owner of an nft and total_supply