async void Handle_Clicked(object sender, System.EventArgs e)
 {
     if (Validates.validateBook(identificationEditor.Text, ageEditor.Text, nameEditor.Text))
     {
         if (bookController.availableBook(flight, nameEditor.Text, ageEditor.Text, identificationEditor.Text))
         {
             bookController.createBook(flight, nameEditor.Text, ageEditor.Text, identificationEditor.Text);
         }
         else
         {
             await App.Current.MainPage.DisplayAlert("Alert", "No chairs available", "OK");
         }
     }
     else
     {
         await App.Current.MainPage.DisplayAlert("Alert", "Fill all fields", "OK");
     }
 }