code: def comment_form(context, object):
      
      user = context.get("user")
      form_class = context.get("form", CommentForm)
      form = form_class(obj=object, user=user)
      return form
docs: Usage:
          {% comment_form obj as comment_form %}
      Will read the `user` var out of the contex to know if the form should be
      form an auth'd user or not.