code: def on_download_button_click(self, btn) -> None:
          "Download button click handler: validate search term and download images."
          term = self._search_input.value
          limit = int(self._count_input.value)
          size = self._size_input.value
          if not self.validate_search_input(): return
          self.clear_imgs()
          downloaded_images = download_google_images(self._path, term, n_images=limit, size=size)
          self.display_images_widgets(downloaded_images[:min(limit, 12)])
          self._preview_header.value = self._download_complete_heading
          self.render(f on_download_button_click(self, btn) -> None:
          "Download button click handler: validate search term and download images."
          term = self._search_input.value
          limit = int(self._count_input.value)
          size = self._size_input.value
          if not self.validate_search_input(): return
          self.clear_imgs()
          downloaded_images = download_google_images(self._path, term, n_images=limit, size=size)
          self.display_images_widgets(downloaded_images[:min(limit, 12)])
          self._preview_header.value = self._download_complete_heading
          self.render()
docs: Download button click handler: validate search term and download images.