code: func (sr StatelessPrebindExample) Prebind(pc *framework.PluginContext, pod *v1.Pod, nodeName string) *framework.Status {
  	if pod == nil {
  		return framework.NewStatus(framework.Error, fmt.Sprintf("pod cannot be nil"))
  	}
  	if pod.Namespace != "foo" {
  		return framework.NewStatus(framework.Unschedulable, "only pods from 'foo' namespace are allowed")
  	}
  	return nil
  }
docs: // Prebind is the functions invoked by the framework at "prebind" extension point.