code: public LocalSecondaryIndex localSecondaryIndex(final String indexName) {
          if (!localSecondaryIndexes.containsKey(indexName)) {
              return null;
          }
          final LocalSecondaryIndex lsi = localSecondaryIndexes.get(indexName);
          final LocalSecondaryIndex copy = new LocalSecondaryIndex().withIndexName(lsi.getIndexName());
          copy.withProjection(new Projection().withProjectionType(lsi.getProjection().getProjectionType()));
          for (final KeySchemaElement key : lsi.getKeySchema()) {
              copy.withKeySchema(new KeySchemaElement(key.getAttributeName(), key.getKeyType()));
          }
          return copy;
      }
docs: Gets the local secondary index by name.
  @param indexNames The index name.
  @return The local secondary index, or null.