def test_empty(self):
        ticks = TickDataSeries()
        self.assertTrue(ticks.empty())

        ticks.append(10.0, 1000, 999.9, '2015-12-17 14:55:00')

        self.assertFalse(ticks.empty())
    def test_empty(self):
        ticks = TickDataSeries()
        self.assertTrue(ticks.empty())

        ticks.append(10.0, 1000, 999.9, '2015-12-17 14:55:00')

        self.assertFalse(ticks.empty())