Merge two ranges with step == 1.

    Parameters
    ----------
    a : range
        The first range.
    b : range
        The second range.

def merge(a, b):
    """Merge two ranges with step == 1.

    Parameters
    ----------
    a : range
        The first range.
    b : range
        The second range.
    """
    _check_steps(a, b)
    return range(min(a.start, b.start), max(a.stop, b.stop))