code: def launch_app(self, tree_path):
          '''用默认的程序打开这个文件链接.'''
          file_type = self.liststore[tree_path][TYPE_COL]
          app_infos = Gio.AppInfo.get_recommended_for_type(file_type)
          if app_infos:
              self.launch_app_with_app_info(app_infos[0])
          else:
              pasf launch_app(self, tree_path):
          '''用默认的程序打开这个文件链接.'''
          file_type = self.liststore[tree_path][TYPE_COL]
          app_infos = Gio.AppInfo.get_recommended_for_type(file_type)
          if app_infos:
              self.launch_app_with_app_info(app_infos[0])
          else:
              pass
docs: 用默认的程序打开这个文件链接.