code: func (s *SubnetKey) FromString(str string) error {
  	if str == "" || !strings.Contains(str, "/") {
  		return types.BadRequestErrorf("invalid string form for subnetkey: %s", str)
  	}
  
  	p := strings.Split(str, "/")
  	if len(p) != 3 && len(p) != 5 {
  		return types.BadRequestErrorf("invalid string form for subnetkey: %s", str)
  	}
  	s.AddressSpace = p[0]
  	s.Subnet = fmt.Sprintf("%s/%s", p[1], p[2])
  	if len(p) == 5 {
  		s.ChildSubnet = fmt.Sprintf("%s/%s", p[3], p[4])
  	}
  
  	return nil
  }
docs: // FromString populates the SubnetKey object reading it from string