prow/github/fakegithub/fakegithub.go
func (f *FakeClient) RemoveLabel(owner, repo string, number int, label string) error {
	labelString := fmt.Sprintf("%s/%s#%d:%s", owner, repo, number, label)
	if !sets.NewString(f.IssueLabelsRemoved...).Has(labelString) {
		f.IssueLabelsRemoved = append(f.IssueLabelsRemoved, labelString)
		return nil
	}
	return fmt.Errorf("cannot remove %v from %s/%s/#%d", label, owner, repo, number)
}
func (f *FakeClient) RemoveLabel(owner, repo string, number int, label string) error {
	labelString := fmt.Sprintf("%s/%s#%d:%s", owner, repo, number, label)
	if !sets.NewString(f.IssueLabelsRemoved...).Has(labelString) {
		f.IssueLabelsRemoved = append(f.IssueLabelsRemoved, labelString)
		return nil
	}
	return fmt.Errorf("cannot remove %v from %s/%s/#%d", label, owner, repo, number)
}
// RemoveLabel removes a label