def __init__(self, assets_dir=None, requirements_file="requirements.yml"):
        self.assets_dir = assets_dir or Path(".") / "assets"
        self.requirements = GroupedRequirements()
        self.requirements.load(requirements_file)
        self.temp_dir = mkdtemp()
def remove_item(self, item):
    item_position = self._get_item_position(item)
    if item_position < len(self._items) - 1:
      next_item_position = item_position + 1
      self._items[next_item_position].item_widget.grab_focus()