code: def serve_record(self, environ, coll='$root', url=''):
          
          if coll in self.warcserver.list_fixed_routes():
              return WbResponse.text_response('Error: Can Not Record Into Custom Collection "{0}"'.format(coll))
  
          return self.serve_content(environ, coll, url, record=True)
docs: Serve a URL's content from a WARC/ARC record in replay mode or from the live web in
          live, proxy, and record mode.
  
          :param dict environ: The WSGI environment dictionary for the request
          :param str coll: The name of the collection the record is to be served from
          :param str url: The URL for the corresponding record to be served if it exists
          :return: WbResponse containing the contents of the record/URL
          :rtype: WbResponse