def test_iadd(self, evt):
        rval = event.ReturnValue(append_events=[evt])
        rval2 = event.ReturnValue(eat=True, append_events=[evt])
        rset = event.ResultSet()

        rset += rval
        rset += rval2
        rset += None
        assert rset.eat
        assert rset.append_events == [evt, evt]
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]