_chooseArticleSubTitle() {
    let source = this.source;
    if (source === "youtube") {
      return this._data.article_title;
    } else {
      return "";
    }
  }
/**
   * Formula to find the normalized article sub title for an Article
   *
   * @returns {string}  - The normalized article subtitle
   * @private
   */
Formula to find the normalized article sub title for an Article
@returns {string}  - The normalized article subtitle
@private
Formula to find the normalized article sub title for an Article @returns { string } - The normalized article subtitle @private
_chooseArticleSubTitle() {
    let source = this.source;
    if (source === "youtube") {
      return this._data.article_title;
    } else {
      return "";
    }
  }
_chooseArticleSubTitle ( ) { let source = this . source ; if ( source === "youtube" ) { return this . _data . article_title ; } else { return "" ; } }
Formula to find the normalized article sub title for an Article
 @returns {string}  - The normalized article subtitle
 @private
Formula to find the normalized article sub title for an Article @returns { string } - The normalized article subtitle @private