code: func GetOldRCs(deployment extensions.Deployment, c client.Interface) ([]*api.ReplicationController, error) {
  	return GetOldRCsFromLists(deployment, c,
  		func(namespace string, options api.ListOptions) (*api.PodList, error) {
  			return c.Pods(namespace).List(options)
  		},
  		func(namespace string, options api.ListOptions) ([]api.ReplicationController, error) {
  			rcList, err := c.ReplicationControllers(namespace).List(options)
  			return rcList.Items, err
  		})
  }
docs: // GetOldRCs returns the old RCs targeted by the given Deployment; get PodList and RCList from client interface.