code: func PublicKeysFromFile(file string) ([]interface{}, error) {
  	data, err := ioutil.ReadFile(file)
  	if err != nil {
  		return nil, err
  	}
  	keys, err := ParsePublicKeysPEM(data)
  	if err != nil {
  		return nil, fmt.Errorf("error reading public key file %s: %v", file, err)
  	}
  	return keys, nil
  }
docs: // PublicKeysFromFile returns the public keys in rsa.PublicKey or ecdsa.PublicKey format from a given PEM-encoded file.
  // Reads public keys from both public and private key files.