code: func exclude(files []string, exclude ...string) []string {
  	var s []string
  Outer:
  	for _, f := range files {
  		for _, e := range exclude {
  			if f == e {
  				continue Outer
  			}
  		}
  		s = append(s, f)
  	}
  	return s
  }
docs: // exclude returns files, excluding specified files.