code: func (ns NameSpace) Fprint(w io.Writer) {
  	fmt.Fprint(w, "name space {\n")
  	var all []string
  	for mtpt := range ns {
  		all = append(all, mtpt)
  	}
  	sort.Strings(all)
  	for _, mtpt := range all {
  		fmt.Fprintf(w, "\t%s:\n", mtpt)
  		for _, m := range ns[mtpt] {
  			fmt.Fprintf(w, "\t\t%s %s\n", m.fs, m.new)
  		}
  	}
  	fmt.Fprint(w, "}\n")
  }
docs: // Fprint writes a text representation of the name space to w.