def test_get_inverse(self): x = TimeSeries([ (datetime.date(2001, 12, 31), 1), (datetime.date(2002, 12, 31), 2), (datetime.date(2003, 12, 31), 5), ]) y = x.get_inverse() self.assertEqual(y.get(), [ (datetime.date(2001, 12, 31), 1.0), (datetime.date(2002, 12, 31), 0.5), (datetime.date(2003, 12, 31), 0.2), ])