code: def _postrun(cls, span, obj, **kwargs):
          
          span.set_tag("response.status_code", obj.status_code)
          span.set_tag(
              "response.content_lenght", len(getattr(obj, 'content', ""))
          )
docs: Trigger to execute just before closing the span
  
          :param opentracing.span.Span  span: the SpanContext instance
          :param Any obj: Object to use as context
          :param dict kwargs: additional data