docs: def document(self):
          """Render the error document"""
          resp = request.environ.get('pylons.original_response')
          content = literal(resp.body) or cgi.escape(request.GET.get('message'))
          page = error_document_template % \
              dict(prefix=request.environ.get('SCRIPT_NAME', ''),
                   code=cgi.escape(request.GET.get('code', str(resp.status_int))),
                   message=content)
          return page