Function which creates the File Picker

    createPicker() {
      console.log("Create Picker", google.picker);
      if (this.pickerApiLoaded && this.oauthToken) {
        var picker = new google.picker.PickerBuilder()
          .enableFeature(google.picker.Feature.MULTISELECT_ENABLED)
          .addView(google.picker.ViewId.DOCS)
          .setOAuthToken(this.oauthToken)
          .setDeveloperKey("AIzaSyBaQZlYTmndQYCcdlkHoVtBzpZYandwaaA")
          .setCallback(this.pickerCallback)
          .build();
        picker.setVisible(true);
      }
    }