show$(title: string, description: string): Observable<boolean> {
        // Change modal content
        this.title = title;
        this.description = description;

        // Prepare return value
        this._confirmationSource = new Subject<boolean>();
        const confirmation$ = this._confirmationSource.asObservable();

        // Show modal
        this.modal.show();

        return confirmation$;
    }

 public hideChildModal():void {
   this.childModal.hide();
 }

 public showChildModal():void {
   this.childModal.show();
 }

 // invoked by the parent
 show() {
   this.modal.show();
 }

 result => {
     this.settingAritcleModel.hide();
     this.router.navigate(['/']);
 }

 showSettingModel() {
     this.settingAritcleModel.show();
 }

 showModal() {
   this.messages = [];
   this.modal.show();
 }

 no() {
     this._confirmationSource.next(false);
     this.modal.hide();
 }

 yes() {
     this._confirmationSource.next(true);
     this.modal.hide();
 }