def maybe_add(d, exclude_false=False, **kws):
    """
    Adds keywork argumnts to a dict if their values are not None.

    Parameters
    ----------
    d: dict
        The dictionary to add to.

    exclude_false: bool
        Exclue keys whose values are false.

    kws: dict
        The keys to maybe add

    """
    for k, v in kws.items():
        if v is not None:
            d[k] = v

    return d