Golang中的静态全局变量

I am new in Go language and I need some help. I have declared a global variable but the problem is that it does not keep its value. It would be solved with a static variable but no such variables exist in Go. How should I solve this?

gIDifelseLearner

I have to mention that NewLearner is called twice from two different files from different packages.

func NewLearner(name string, peerURLs types.URLs, clusterName string, now *time.Time) *Learner {

    l := &Learner{
        RaftAttributes: RaftAttributes{PeerURLs: peerURLs.StringSlice()},
        Attributes:     Attributes{Name: name},
    }

    var b []byte
    sort.Strings(l.PeerURLs)
    for _, p := range l.PeerURLs {
        b = append(b, []byte(p)...)
    }

    b = append(b, []byte(clusterName)...)
    if now != nil {
        b = append(b, []byte(fmt.Sprintf("%d", now.Unix()))...)
        hash := sha1.Sum(b)
        l.ID = types.ID(binary.BigEndian.Uint64(hash[:8]))
        gID=l.ID
        return l
    }  else {
        l.ID = gID
        return l    
    }

}