def revrange(a,b):
    """
    Returns the tuple (b-1, b-2, ..., a)

    Note that this tuple is the reverse of tuple(range(a,b))

    Parameter a: the "start" of the range
    Precondition: a is an int <= b

    Parameter b: the "end" of the range
    Precondition: b is an int >= a
    """
    assert type(a) == int and a <= b
    assert type(b) == int

    tup1 = tuple(range(a,b))
    tup2 = tup1[::-1]
    tup = ()
    result = tup
    for i in tup2:
        if a < b:
            result = tup2
        else:
            result = tup
    return result
    #pass