def METHOD_NAME():
    """
    Determines the default Lightkurve cache directory name and creates the
    directory if it doesn't exist. If the directory cannot be access or created,
    then it returns the current directory (``"."``).
    This directory is typically ``$HOME/.lightkurve/cache``, but if the
    XDG_CACHE_HOME environment variable is set and the
    ``$XDG_CACHE_HOME/lightkurve`` directory exists, it will be that directory.
    If neither exists, the former will be created and symlinked to the latter.
    The value can be also configured via ``cache_dir`` configuration parameter.
    Returns
    -------
    cachedir : str
        The absolute path to the cache directory.
    Examples
    --------
    To configure "/my_research/data" as the `cache_dir`, users can set it:
    1. in the user's ``lightkurve.cfg`` file::
        [config]
        cache_dir = /my_research/data
    2. at run time::
        import lightkurve as lk
        lk.conf.cache_dir = '/my_research/data'
    See :ref:`configuration <api.config>` for more information.
    """
    from .. import conf
    cache_dir = conf.cache_dir
    if cache_dir is None or cache_dir == "":
        cache_dir = astropyconfig.METHOD_NAME(ROOTNAME)
    cache_dir = _ensure_cache_dir_exists(cache_dir)
    cache_dir = os.path.abspath(cache_dir)
    return cache_dir