def METHOD_NAME(self, *, key_id: str) -> Optional[pathlib.Path]:
    """Find snap key asset matching key_id.
    The key asset much be named with the last 8 characters of the key
    identifier, in upper case.
    :param key_id: Key ID to search for.
    :returns: Path of key asset if match found, otherwise None.
    """
    key_file = key_id[-8:].upper() + ".asc"
    key_path = self._key_assets / key_file
    if key_path.exists():
        return key_path
    return None