code: func GetNewReplicaSet(deployment extensions.Deployment, c clientset.Interface) (*extensions.ReplicaSet, error) {
  	return GetNewReplicaSetFromList(deployment, c,
  		func(namespace string, options api.ListOptions) ([]extensions.ReplicaSet, error) {
  			rsList, err := c.Extensions().ReplicaSets(namespace).List(options)
  			return rsList.Items, err
  		})
  }
docs: // GetNewReplicaSet returns a replica set that matches the intent of the given deployment; get ReplicaSetList from client interface.
  // Returns nil if the new replica set doesn't exist yet.