def keysym_group(ks1, ks2):
    """Generates a group from two *keysyms*.

    The implementation of this function comes from:

        Within each group, if the second element of the group is ``NoSymbol``,
        then the group should be treated as if the second element were the same
        as the first element, except when the first element is an alphabetic
        *KeySym* ``K`` for which both lowercase and uppercase forms are
        defined.

        In that case, the group should be treated as if the first element were
        the lowercase form of ``K`` and the second element were the uppercase
        form of ``K``.

    This function assumes that *alphabetic* means *latin*; this assumption
    appears to be consistent with observations of the return values from
    ``XGetKeyboardMapping``.

    :param ks1: The first *keysym*.

    :param ks2: The second *keysym*.

    :return: a tuple conforming to the description above
    """