code: func NewPool(filename string) (*x509.CertPool, error) {
  	certs, err := CertsFromFile(filename)
  	if err != nil {
  		return nil, err
  	}
  	pool := x509.NewCertPool()
  	for _, cert := range certs {
  		pool.AddCert(cert)
  	}
  	return pool, nil
  }
docs: // NewPool returns an x509.CertPool containing the certificates in the given PEM-encoded file.
  // Returns an error if the file could not be read, a certificate could not be parsed, or if the file does not contain any certificates