Return selected value from Actionsheet component

Ionic Framework ionic-v3
1

I am using the ActionSheet component to get the user to select an image either from the camera or the gallery.
What I would like to do is call a service function getPicture that will show the ActionSheet and depending on the user selection will resolve with the photo either from camera or gallery.

public getPicture() {

let actionSheet = ActionSheet.create({
  title: 'Select Source',
  buttons: [
    {
      text: 'Take Picture',
      icon: this._platform.is('android') ? 'camera' : null,
      handler: () => {
        this.UseCamera(Camera.PictureSourceType.CAMERA)
          .then(WHAT NOW?);
      }
    }, {
      text: 'Import From Library',
      icon: this._platform.is('android') ? 'camera' : null,
      handler: () => {
        this.UseCamera(Camera.PictureSourceType.PHOTOLIBRARY)
          .then(WHAT NOW?);
      }
    }, {
      text: 'Cancel',
      role: 'cancel',
      icon: this._platform.is('android') ? 'close' : null,
      handler: () => {
      }
    }
  ]
});
this._nav.present(actionSheet);

}

//Note this.UseCamera(Camera.PictureSourceType.CAMERA) returns a promise that resolved with the Base64 photo string

How can I resolve the string to the caller of getPicture?
One option would be to use an eventEmitter to emit an event on the handler with the given data, but I am not sure it will work, and not crazy about it. Is there a clean way to go about this?