Find Error code from the given error in golang

regex.go

package main

import ("regexp"
	"errors"
	"fmt"
)
var errExtract = regexp.MustCompile(`Err (\d+)`)
func main(){
	customErr := errors.New("Err 1024 ; sql must use 3 rows but define 4 in scan")
	match := errExtract.FindStringSubmatch(customErr.Error())
	fmt.Print(match)
}