def test_sub(self):
    ' Tests the subtraction operator.\n        '
    result = (self.v2 - self.v3)
    expected_result = Vector2D((- 3.5), 3.5)
    self.assertEqual(result, expected_result)
Tests the subtraction operator.
def test_sub(self):
    ' \n        '
    result = (self.v2 - self.v3)
    expected_result = Vector2D((- 3.5), 3.5)
    self.assertEqual(result, expected_result)