going through examples -- getting errors ('address' doesn't refer to an import prefix)

[timfong888]

This is from the example documentation:

import 'dart:math'; //used for the random number generator

import 'package:dart_web3/dart_web3.dart';
// You can create Credentials from private keys
Credentials fromHex = EthPrivateKey.fromHex("c87509a[...]dc0d3");

// Or generate a new key randomly
var rng = Random.secure();
Credentials random = EthPrivateKey.createRandom(rng);

// In either way, the library can derive the public key and the address
// from a private key:
var address = await credentials.extractAddress();
print(address.hex);

However, in my dart application, this creates errors.

I modified some of the content, but it still gets an error:

import 'package:dart_web3/dart_web3.dart';
import 'package:http/http.dart';
import 'dart:math'; //used for the random number generator

// Or generate a new key randomly
var rng = Random.secure();
final EthPrivateKey credentials = EthPrivateKey.createRandom(rng);

var address = await credentials.extractAddress();
//print(address.hex);

My changes solves for the type errors for credentials. But I still get an await error saying its missing async.

Error: 'address.hex' can't be used as a type because 'address' doesn't refer to an import prefix