async void Handle_AcceptSignature(object sender, System.EventArgs e)
 {
     if (signature.IsBlank == false)
     {
         // export the signature bitmap
         using (var stream = await signature.GetImageStreamAsync(SignatureImageFormat.Png))
         {
             hif.TipsSignature?.Delete();
             hif.TipsSignature = HifImage.FromPngStream(stream);
         }
         await Navigation.PopToRootAsync(true);
     }
     else
     {
         await DisplayAlert("Please sign", "A signature is needed as proof that you read these tips.", "OK");
     }
 }
 async void Handle_AcceptSignature(object sender, EventArgs e)
 {
     if (signature.IsBlank == false)
     {
         // export the signature bitmap
         using (var stream = await signature.GetImageStreamAsync(SignatureImageFormat.Png))
         {
             Person.NoIncomeSingurate?.Delete();
             Person.NoIncomeSingurate = HifImage.FromPngStream(stream);
         }
         await Navigation.PopToRootAsync(true);
     }
     else
     {
         await DisplayAlert("Please sign", "A signature is needed as proof.", "OK");
     }
 }