def fill_kwargs(kwargs):
    """Give the kwargs dict default options."""

    defaults = {
        "strandedness": None,
        "overlap": True,
        "how": None,
        "invert": None,
        "new_pos": None,
        "suffixes": ["_a", "_b"],
        "suffix": "_b",
        "sparse": {
            "self": False,
            "other": False
        }
    }

    defaults.update(kwargs)

    return defaults