*
     * @param item The SuggestItem with new data
     * @param existingSource The existing source map from OpenSearch
     * @return A merged source map
     */
    public static Map<String, Object> toUpdatedSource(final SuggestItem item, final Map<String, Object> existingSource) {
        final Map<String, Object> map = new HashMap<>();
        map.put(FieldNames.TEXT, item.getText());

     * @return The updated source map.
     */
    public Map<String, Object> getUpdatedSource(final Map<String, Object> existingSource) {
        return SuggestItemSerializer.toUpdatedSource(this, existingSource);
    }

    /**
     * Concatenates values to a destination list, avoiding duplicates.
     * @param dest The destination list.
     * @param newValues The new values to add.