def get_installed_pypackages():
    return {p.project_name.lower(): p for p in pkg_resources.working_set}
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]