code: func (m *MultiResolver) getResolveValidator(name string) ([]ResolveValidator, error) {
  	rs := m.resolvers[""]
  	tld := path.Ext(name)
  	if tld != "" {
  		tld = tld[1:]
  		rstld, ok := m.resolvers[tld]
  		if ok {
  			return rstld, nil
  		}
  	}
  	if len(rs) == 0 {
  		return rs, NewNoResolverError(tld)
  	}
  	return rs, nil
  }
docs: // getResolveValidator uses the hostname to retrieve the resolver associated with the top level domain