code: func (f Fernet) Decrypt(record api.MaybeEncryptedRecord) ([]byte, error) {
  	if record.Algorithm != f.Algorithm() {
  		return nil, fmt.Errorf("record is not a Fernet message")
  	}
  
  	// -1 skips the TTL check, since we don't care about message expiry
  	out := fernet.VerifyAndDecrypt(record.Data, -1, []*fernet.Key{&f.key})
  	// VerifyandDecrypt returns a nil message if it can't be verified and decrypted
  	if out == nil {
  		return nil, fmt.Errorf("no decryption key for record encrypted with %s", f.Algorithm())
  	}
  	return out, nil
  }
docs: // Decrypt decrypts a MaybeEncryptedRecord and returns some bytes