tmp.go

func ImportPiesReport(result pies.Result) error {
	processChan := make(chan error)
	for _, item := range result.Items {
		go func(item pies.Item) {
			p := Part{}
			p.MapPiesData(item)
			processChan <- p.Add()
		}(item)
	}
	<-processChan

	return nil
}

tmp2.go

func ImportPiesReport(result pies.Result) {
	for _, item := range result.Items {
		go ProcessPiesData(item)
	}
}

func ProcessPiesData(item pies.Item) {
	p := Part{}
	p.MapPiesData(item)
	p.Add()
}