code: def setup(app):
      app.add_node(
          extension_node,
          html=(visit_extension_node, depart_extension_node),
          latex=(visit_extension_node, depart_extension_node),
          text=(visit_extension_node, depart_extension_node),
      )
  
      app.add_directive("extension", Extension)
  
file_path: psycopg2/doc/src/tools/lib/dbapi_extension.py
imports: from docutils import nodes
  from sphinx.locale import _
  from docutils.parsers.rst import Directive
label_desc: Use image node_id 3 for calling a global function with example usage: setup(app) without return types