code: def setup(app) -> Dict[str, Any]:
      
      app.connect("doctree-read", on_doctree_read)
      app.connect("builder-inited", on_builder_inited)
      app.add_css_file("uqbar.css")
      app.add_node(
          nodes.classifier, override=True, html=(visit_classifier, depart_classifier)
      )
      app.add_node(
          nodes.definition, override=True, html=(visit_definition, depart_definition)
      )
      app.add_node(nodes.term, override=True, html=(visit_term, depart_term))
      return {
          "version": uqbar.__version__,
          "parallel_read_safe": True,
          "parallel_write_safe": True,
      }
docs: Sets up Sphinx extension.