code: def scale_rc(self, manifest_filename, namespace="default", num_replicas=0):
          
          rc_manifest, rc_manifest_json = util.load_yaml(filename=manifest_filename)
          logging.debug("%s" %(rc_manifest_json))
          rc_path = "".join(["/api/v1/namespaces/", namespace, "/replicationcontrollers/", rc_manifest["metadata"]["name"]])
          rc_manifest["spec"]["replicas"] = num_replicas
          res = self.execute_operation(method="PUT", ops_path=rc_path, payload=util.serialize_tojson(rc_manifest))
          try:
              rc_url = res.json()["metadata"]["selfLink"]
          except KeyError:
              raise ResourceCRUDException("".join(["Sorry, can not scale the RC: ", rc_manifest["metadata"]["name"]]))
          logging.info("I scaled the RC %s at %s to %d replicas" %(rc_manifest["metadata"]["name"], rc_url, num_replicas))
          return (res, rc_url)
docs: Changes the replicas of an RC based on a manifest.
          Note that it defaults to 0, meaning to effectively disable this RC.
  
          :Parameters:
             - `manifest_filename`: The manifest file containing the ReplicationController definition, for example: `manifest/nginx-webserver-rc.yaml`
             - `namespace`: In which namespace the RC is, defaulting to `default`
             - `num_replicas`: How many copies of the pods that match the selector are supposed to run