code: func New(metadata map[string]string) ([]*x509.Certificate, error) {
  	roots := initSystemRoots()
  	if len(roots) == 0 {
  		return nil, errors.New("transport: unable to find system roots")
  	}
  	return roots, nil
  }
docs: // New returns a new certificate pool loaded with the system
  // roots. The provided argument is not used; it is included for
  // compatibility with other functions.