def writesolution_kwargs(**kwargs):
    """Unpack keyword arguments related to write-solution-to-file."""
    nwrite = kwargs.get("nWrite", 10)
    fname = kwargs.get("FileName", "solution.dat")
    nmax = kwargs.get("nMax", None)
    dx = kwargs.get("dX", None)
    dy = kwargs.get("dY", None)
    var_dict = {
        "nWrite": nwrite,
        "FileName": fname,
        "nMax": nmax,
        "dX": dx,
        "dY": dy
        }
    return var_dict