How to use the @jupyter-widgets/controls.SelectModel function in @jupyter-widgets/controls

defaults: function() {
    return _.extend({}, widgets.SelectModel.prototype.defaults.apply(this), {
      _view_name: "ComboBoxView",
      _model_name: "ComboBoxModel",
      _model_module: 'beakerx',
      _view_module: 'beakerx'
    });
  }
});

*  You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

var widgets = require('@jupyter-widgets/controls');
var _ = require('underscore');
var comboBox = require('../comboBox/jQueryComboBox');

var ComboBoxModel = widgets.SelectModel.extend({
  defaults: function() {
    return _.extend({}, widgets.SelectModel.prototype.defaults.apply(this), {
      _view_name: "ComboBoxView",
      _model_name: "ComboBoxModel",
      _model_module: 'beakerx',
      _view_module: 'beakerx'
    });
  }
});

var ComboBoxView = widgets.SelectView.extend({
  render: function() {
    ComboBoxView.__super__.render.apply(this);

    this.el.classList.add('widget-combobox');
    this.$select = $(this.el).find('select');