The given string does not have the correct begin/end markers expected in a PEM file.

I'm using package:googleapis_auth/auth_io.dart to login as a service account in Flutter.

`

Future obtainCredentials() async {
var accountCredentials = ServiceAccountCredentials.fromJson({
"private_key_id": "de1234567890",
"private_key": "my-services-12345",
"client_email":
"test@my-services-12345.iam.gserviceaccount.com",
"client_id": "1234567890",
"type": "service_account"
});
var scopes = ["https://www.googleapis.com/auth/cloud-platform"];

var client = http.Client();
AccessCredentials credentials =
await obtainAccessCredentialsViaServiceAccount(
accountCredentials, scopes, client);

client.close();
debugPrint(credentials.toString());`

But as soon the script starts I'm getting the error

`The given string does not have the correct begin/end markers expected in a PEM file.`
pointing to
`ServiceAccountCredentials.fromJson`