getTokenBalance method
for token:
Implementation
Future<dynamic> getTokenBalance(String contractAddress, {required String address}) async {
List<dynamic> params = [EthereumAddress.fromHex(address)];
///
var ret = (await _readFromContract('BasicToken', contractAddress, 'balanceOf', params)).first;
print('getTokenBalance: $contractAddress, $address, result: $ret');
return ret;
}