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_either():
    """Either f or g."""
    p = are.above(3) | are.below(2)
    ps = [p(x) for x in range(1, 6)]
    assert ps == [True, False, False, True, True]