[notebook_shortcode]object has no attribute 'handler'

[ifurther]

Traceback (most recent call last): File "/home/user/lib/bin/nikola", line 8, in sys.exit(main()) File "/home/user/lib/lib/python3.8/site-packages/nikola/main.py", line 166, in main _ = DN.run(oargs) File "/home/user/lib/lib/python3.8/site-packages/nikola/main.py", line 352, in run self.nikola.init_plugins(load_all=True) File "/home/user/lib/lib/python3.8/site-packages/nikola/nikola.py", line 1176, in init_plugins self._activate_plugins_of_category("ShortcodePlugin") File "/home/user/lib/lib/python3.8/site-packages/nikola/nikola.py", line 1334, in _activate_plugins_of_category plugin_info.plugin_object.set_site(self) File "/home/user/docs/plugins/notebook_shortcode/notebook_shortcode.py", line 47, in set_site super(NotebookShortcodePlugin, self).set_site(site) File "/home/user/lib/lib/python3.8/site-packages/nikola/plugin_categories.py", line 492, in set_site site.register_shortcode(self.name, self.handler) AttributeError: 'NotebookShortcodePlugin' object has no attribute 'handler'