code: public DynamoDBQueryExpression<T> withRangeKeyCondition(String rangeKeyAttributeName, Condition rangeKeyCondition) {
          if ( rangeKeyConditions == null )
              rangeKeyConditions = new HashMap<String, Condition>();
          rangeKeyConditions.put(rangeKeyAttributeName, rangeKeyCondition);
          return this;
      }
docs: Sets one range key condition for this query, using the attribute name of
  the range key. All range key attributes for the table must be specified
  by using {@link DynamoDBRangeKey} or {@link DynamoDBIndexRangeKey} annotations
  before executing the query.
  <dl>
  <dt>If the attribute is the primary range key</dt>
  <dd>users should NOT set any index name for this query.</dd>
  <dt>If the attribute is an index range key</dt>
  <dd>
  {@link DynamoDBMapper} will automatically set the index name if the
  range key is annotated as only used by one local secondary index,
  otherwise users must set the index name manually by either
  {@link DynamoDBQueryExpression#setIndexName(String)} or
  {@link DynamoDBQueryExpression#withIndexName(String)}.
  </dd>
  </dl>
  
  @param rangeKeyAttributeName
  This can be either the primary range key of the table or an
  index range key.
  
  @param rangeKeyCondition
  Condition specified on the given range key for this query.