You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: wrapped_erc20s.rs
    path of file: ./repos/namada/crates/ethereum_bridge/src/storage
    
    the code of the file until where you have to start completion: //! Functionality for accessing the multitoken subspace

use eyre::eyre;
use namada_core::address::{Address, InternalAddress};
pub use namada_core::eth_bridge_pool::{
    erc20_nut_address as nut, erc20_token_address as token,
};
use namada_core::ethereum_events::EthAddress;
use namada_core::storage::{self, DbKeySeg};
use namada_trans_token::storage_key::{
    balance_key, minted_balance_key, MINTED_STORAGE_KEY,
};

/// Represents the type of a key relating to a wrapp
    
    fn test_from_multitoken_key_for_key() {
        // supply key
        let wdai_supply = Key {
            asset: DAI_ERC20_ETH_ADDRESS,
            suffix: KeyType::Supply,
        };
        let key: storage::Key = (&wdai_supply).into();
        assert_matches!(
            &key.segments[..],
            [
                DbKeySeg::AddressSeg(multitoken_addr),
                DbKeySeg::AddressSeg(token_addr),
                DbKeySeg::StringSeg(balance_key_seg),
                DbKeySeg::StringSeg(supply_key_seg),
            ] if multitoken_addr == &MULTITOKEN_ADDRESS &&
            token_addr == &dai_erc20_token() &&
            balance_key_seg == BALANCE_STORAGE_KEY &&
            supply_key_seg == MINTED_STORAGE_KEY
        );

        // balance key
        let wdai_balance = Key {
            asset: DAI_ERC20_ETH_ADDRESS,
            suffix: KeyType::Balance {
                owner: Address::from_str(ARBITRARY_OWNER_ADDRESS).unwrap(),
            },
        };
        let key: storage::Key = (&wdai_balance).into();
        assert_matches!(
            &key.segments[..],
            [
                DbKeySeg::AddressSeg(multitoken_addr),
                DbKeySeg::AddressSeg(token_addr),
                DbKeySeg::StringSeg(balance_key_seg),
                DbKeySeg::AddressSeg(owner_addr),
            ] if multitoken_addr == &MULTITOKEN_ADDRESS &&
            token_addr == &dai_erc20_token() &&
            balance_key_seg == BALANCE_STORAGE_KEY &&
            owner_addr == &Address::decode(ARBITRARY_OWNER_ADDRESS).unwrap()
        );
    }