Unable to read data in AWS android mobile while using DynamoDB

Question

I started to develop an android app using Amazon Mobile hub (my first time) and Android Studio 3.0.1, and I tried to follow the tutorials

But I keep on getting errors like:

com.amazonaws.mobileconnectors.dynamodbv2.dynamodbmapper.DynamoDBMappingException: No method annotated with interface com.amazonaws.mobileconnectors.dynamodbv2.dynamodbmapper.DynamoDBRangeKey for class class com.amazonaws.models.nosql.ParkInfoDO.

I have a

table park_info
partition key:park_id

Is there something wrong with my code?

public void readData() {
    final IdentityManager identityManager = IdentityManager.getDefaultIdentityManager();
    new Thread(new Runnable() {
        @Override
        public void run() {

            ParkInfoDO parkItem = dynamoDBMapper.load(
                    ParkInfoDO.class,
                    identityManager.getCachedUserID(),
                    "P");

            // Item read
            Log.d("Park Item:", parkItem.toString());
        }
    }).start();
}