def __init__(self, groups=None):
        super(GroupedRequirements, self).__init__(NamedRequirements)
        self.groups = groups or self.default_groups
        self.filename = None
        self.create_default_groups()
def test_between():
    """Greater than or equal to y and less than z."""
    p = are.between(3, 4)
    ps = [p(x) for x in range(1, 6)]
    assert ps == [False, False, True, False, False]