// Add add pool endpoints
func (l *EndpointServerPools) Add(zeps PoolEndpoints) error {
	existSet := set.NewStringSet()
	for _, zep := range *l {
		for _, ep := range zep.Endpoints {
			existSet.Add(ep.String())
		}
	}
	// Validate if there are duplicate endpoints across serverPools
	for _, ep := range zeps.Endpoints {
		if existSet.Contains(ep.String()) {
			return fmt.Errorf("duplicate endpoints found")
		}
	}