docs: public void setBookVersion(final String bookVersion) {
          if (bookVersion == null && this.bookVersion == null) {
              return;
          } else if (bookVersion == null) {
              removeChild(this.bookVersion);
              this.bookVersion = null;
          } else if (this.bookVersion == null) {
              this.bookVersion = new KeyValueNode<String>(CommonConstants.CS_BOOK_VERSION_TITLE, bookVersion);
              appendChild(this.bookVersion, false);
          } else {
              this.bookVersion.setValue(bookVersion);
          }
      }