How to configure checkbox in alert controller and return value in Ionic 4?

I have a button that logs an event. When the button is clicked it automatically picks the chosen date from a calendar. after this the user would have to register two boolean attributes. I don't know how to do this efficiently. Can someone help me?

async cadastrarPresenca() {
let ida: boolean;
let volta: boolean;


const alert = await this.alertController.create({
  header: 'Confirmar ida e/ou volta',
  inputs: [
    {
      name: 'Ida',
      type: 'checkbox',
      label: 'Ida',
      value: ida,
    },
    {
      name: 'Volta',
      type: 'checkbox',
      label: 'Volta',
      value: volta
    }],
  buttons: [
    {
      text: 'Cancel',
      role: 'cancel',
      cssClass: 'secondary',
      handler: () => {
        console.log('Confirm Cancel');
      }
    }, {
      text: 'Ok',
      handler: () => {
        let start = this.dataSelecionada;
        let end = this.dataSelecionada;
        end.setMinutes(end.getMinutes() + 60);
        let presenca = {
          title: 'Event #' + start.getMinutes(),
          startTime: start,
          endTime: end,
          allDay: false,
          ida: ida,
          volta: volta
        };
        this.firestore.collection('aluno').doc(this.authService.getUsuario().uid).collection('presenca').add(presenca);
      }
    }
  ]
});

await alert.present();