code: func CertsFromFile(file string) ([]*x509.Certificate, error) {
  	pemBlock, err := ioutil.ReadFile(file)
  	if err != nil {
  		return nil, err
  	}
  	certs, err := ParseCertsPEM(pemBlock)
  	if err != nil {
  		return nil, fmt.Errorf("error reading %s: %s", file, err)
  	}
  	return certs, nil
  }
docs: // CertsFromFile returns the x509.Certificates contained 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