def test_change_component_matrix(self) -> None:
        a = Matrix([[1, 2, 3], [2, 4, 5], [6, 7, 8]], 3, 3)
        a.change_component(0, 2, 5)
        self.assertEqual("|1,2,5|\n|2,4,5|\n|6,7,8|\n", str(a))