code: def setup(app):
      
      lexer = MarkdownLexer()
      for alias in lexer.aliases:
          app.add_lexer(alias, lexer)
  
      return dict(version=__version__)
docs: Initializer for Sphinx extension API.
  
          See http://www.sphinx-doc.org/en/stable/extdev/index.html#dev-extensions.