How to use the @material/mwc-base/formable-component-element.js.MDCWebComponentMixin function in @material/mwc-base

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.
*/
import {FormableComponentElement, MDCWebComponentMixin, html} from '@material/mwc-base/formable-component-element.js';
import {classString as c$} from '@polymer/lit-element/lit-element.js';
import {style} from './mwc-slider-css.js';
import {MDCSlider} from '@material/slider';

export class MDCWCSlider extends MDCWebComponentMixin(MDCSlider) {}

export class Slider extends FormableComponentElement {
  static get ComponentClass() {
    return MDCWCSlider;
  }

  static get componentSelector() {
    return '.mdc-slider';
  }

  static get properties() {
    return {
      disabled: {type: Boolean},
      step: {type: Number},
      min: {type: Number},
      max: {type: Number},

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.
*/
import {FormableComponentElement, MDCWebComponentMixin, html} from '@material/mwc-base/formable-component-element.js';
import {style} from './mwc-radio-css.js';
import {SelectionController} from '@material/mwc-base/selection-controller.js';
import {MDCRadio} from '@material/radio';

export class MDCWCRadio extends MDCWebComponentMixin(MDCRadio) {}

export class Radio extends FormableComponentElement {
  static get ComponentClass() {
    return MDCWCRadio;
  }

  static get componentSelector() {
    return '.mdc-radio';
  }

  static get properties() {
    return {
      checked: {type: Boolean},
      disabled: {type: Boolean},
      value: {type: String},
      name: {type: String},