docs: public void setFiles(final List<File> files) {
          if (files == null && this.files == null) {
              return;
          } else if (files == null) {
              removeChild(this.files);
              this.files = null;
          } else if (this.files == null) {
              this.files = new FileList(CommonConstants.CS_FILE_TITLE, files);
              appendChild(this.files, false);
          } else {
              this.files.setValue(files);
          }
      }