code: func (h *Handle) UnmarshalJSON(data []byte) error {
  	var (
  		m   map[string]interface{}
  		b   []byte
  		err error
  	)
  	if err = json.Unmarshal(data, &m); err != nil {
  		return err
  	}
  	h.id = m["id"].(string)
  	bi, _ := json.Marshal(m["sequence"])
  	if err := json.Unmarshal(bi, &b); err != nil {
  		return err
  	}
  	return h.FromByteArray(b)
  }
docs: // UnmarshalJSON decodes json message into Handle