code: func (p *OpenPrinter) ClaimPDF() ([]byte, error) {
  	data, err := httpGET(&p.auth, p.register.InvitePageURL)
  	if err != nil {
  		return nil, fmt.Errorf("ClaimPDF: %v", err)
  	}
  	return data, nil
  }
docs: // ClaimPDF returns the content of a PDF of instructions
  // that can be printed and given to a prospective owner to claim the printer.