code: def on_delete(self, btn):
          "Flag this image as delete or keep."
          btn.button_style = "" if btn.flagged_for_delete else "danger"
          btn.flagged_for_delete = not btn.flagged_for_deletf on_delete(self, btn):
          "Flag this image as delete or keep."
          btn.button_style = "" if btn.flagged_for_delete else "danger"
          btn.flagged_for_delete = not btn.flagged_for_delete
docs: Flag this image as delete or keep.