code: func NewHeaderFromJSON(data string) (*Header, error) {
  	h := &Header{
  		header: new(types.Header),
  	}
  	if err := json.Unmarshal([]byte(data), h.header); err != nil {
  		return nil, err
  	}
  	return h, nil
  }
docs: // NewHeaderFromJSON parses a header from a JSON data dump.