def METHOD_NAME(self) -> bytes:
    """
    Serialize keys into bytes.
    Serialized keys are not encrypted, so be careful how you store/transfer them!
    Returns:
        bytes:
            serialized keys
    """
    if self._keyset is None:
        message = "Keys cannot be serialized before they are generated"
        raise RuntimeError(message)
    serialized_keyset = self._keyset.METHOD_NAME()
    return serialized_keyset