docs: def initialize_renderer(extensions=None):
      """
      Initializes the renderer by setting up the extensions (taking a comma separated
      string or iterable of extensions). These extensions are added alongside with the
      configured always-on extensions.
  
      Returns a markdown renderer instance.
      """
      if extensions is None:
          extensions = []
  
      if isinstance(extensions, str):
          extensions = [extension.strip() for extension in extensions.split(',')]
  
      for extension in getattr(settings, 'MARKYMARK_EXTENSIONS', DEFAULT_MARKYMARK_EXTENSIONS):
          extensions.append(extension)
  
      return markdown.Markdown(extensions=extensions)