How to use the pnotify/dist/es/PNotifyCompat.defaults function in pnotify

*      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.
 * #L%
 */
import { Injectable } from '@angular/core';

import PNotify from 'pnotify/dist/es/PNotifyCompat';
import PNotifyButtons from 'pnotify/dist/es/PNotifyButtons';

PNotify.defaults.styling = 'brighttheme';
PNotify.defaults.icons = 'brighttheme';

@Injectable({ providedIn: 'root' })
export class NotificationService {

    private warningOptions;
    private infoOptions;
    private successOptions;
    private errorOptions;

    constructor() {

        // tslint:disable-next-line:no-unused-expression
        PNotifyButtons; // Initiate the module. Important!

        this.warningOptions = {
            type: 'warning',

*
 *      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.
 * #L%
 */
import { Injectable } from '@angular/core';

import PNotify from 'pnotify/dist/es/PNotifyCompat';
import PNotifyButtons from 'pnotify/dist/es/PNotifyButtons';

PNotify.defaults.styling = 'brighttheme';
PNotify.defaults.icons = 'brighttheme';

@Injectable({ providedIn: 'root' })
export class NotificationService {

    private warningOptions;
    private infoOptions;
    private successOptions;
    private errorOptions;

    constructor() {

        // tslint:disable-next-line:no-unused-expression
        PNotifyButtons; // Initiate the module. Important!

        this.warningOptions = {