def METHOD_NAME(name: str, extension: str) -> str:
    """
    The extension is optional, and the long filename entry explicitly specifies it,
    on the opposite as for short file names.
    """
    lfn_record: str = build_name(name, extension)
    # the name must be terminated with NULL terminator
    # if it doesn't fit into the set of long name directory entries
    if len(lfn_record) % Entry.CHARS_PER_ENTRY != 0:
        return lfn_record + chr(0)
    return lfn_record