- getFullnodeUrl(network): 
    | "https://fullnode.mainnet.sui.io:443"
    | "https://fullnode.testnet.sui.io:443"
    | "https://fullnode.devnet.sui.io:443"
    | "http://127.0.0.1:9000" Parameters
- network: 
    | "mainnet"
    | "testnet"
    | "devnet"
    | "localnet" 
Returns 
    | "https://fullnode.mainnet.sui.io:443"
    | "https://fullnode.testnet.sui.io:443"
    | "https://fullnode.devnet.sui.io:443"
    | "http://127.0.0.1:9000"