code: def setup(app):
      app.add_directive("helloworld", HelloWorld)
  
      return {
          "version": "0.1",
          "parallel_read_safe": True,
          "parallel_write_safe": True,
      }
  
imports: from docutils import nodes
  from docutils.parsers.rst import Directive
label_desc: Use image node_id 1 for calling a global function with example usage: setup(app) and returns: dict