request.addExcludeWord(excludeWord);
        return this;
    }

    /**
     * Sets the query frequency threshold.
     * @param queryFreqThreshold The query frequency threshold.
     * @return This builder instance.
     */
    public PopularWordsRequestBuilder setQueryFreqThreshold(final int queryFreqThreshold) {

     */
    public void addExcludeWord(final String excludeWord) {
        excludeWords.add(excludeWord);
    }

    /**
     * Sets the query frequency threshold.
     * @param queryFreqThreshold The query frequency threshold.
     */
    public void setQueryFreqThreshold(final int queryFreqThreshold) {
        this.queryFreqThreshold = queryFreqThreshold;
    }

    @Override