def METHOD_NAME(self):
    self.assertIsNone(self.scatter.x)
    # Assign list
    self.scatter.x = [1, 2, 3, 4]
    # Stored as list
    self.assertEqual(self.scatter.to_plotly_json()["x"], [1, 2, 3, 4])
    # Returned as tuple
    self.assertEqual(self.scatter.x, (1, 2, 3, 4))