code: public <H,R> T createKey(final H hashKey, final R rangeKey) {
          final T key = StandardBeanProperties.DeclaringReflect.<T>newInstance(targetType);
          if (hashKey != null) {
              final DynamoDBMapperFieldModel<T,H> hk = hashKey();
              hk.set(key, hashKey);
          }
          if (rangeKey != null) {
              final DynamoDBMapperFieldModel<T,R> rk = rangeKey();
              rk.set(key, rangeKey);
          }
          return key;
      }
docs: Creates a new object instance with the keys populated.
  @param <H> The hash key type.
  @param <R> The range key type.
  @param hashKey The hash key.
  @param rangeKey The range key (optional if not present on table).
  @return The new instance.