@classmethod
def _postrun(cls, span, obj, **kwargs):
    """ 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
        """
    span.set_tag('response.status_code', obj.status_code)
    span.set_tag('response.content_lenght', len(getattr(obj, 'content', '')))
