code: func doDec(signer jwt.Signer, in []byte) ([]byte, error) {
  	var err error
  
  	// decode token
  	ut := UnstructuredToken{}
  	err = signer.Decode(bytes.TrimSpace(in), &ut)
  	if err != nil {
  		return nil, err
  	}
  
  	// pretty format output
  	out, err := json.MarshalIndent(&ut, "", "  ")
  	if err != nil {
  		return nil, err
  	}
  
  	return out, nil
  }
docs: // doDec decodes in as a JWT.