docs: public static String credentialReferencePartAsStringIfDefined(ModelNode credentialReferenceValue, String name) throws OperationFailedException {
          assert credentialReferenceValue.isDefined() : credentialReferenceValue;
          ModelNode result = credentialReferenceValue.get(name);
          if (result.isDefined()) {
              return result.asString();
          }
          return null;
      }