def test_subtract(self):
c1 = Complex(-10, 3)
c2 = Complex(1, -2)
self.assertEqual(str(c1.subtract(c2)), "-11.00 + 5.00i", "Should equal '-9.00 + 7.00i'")
def test_subtract(self):
c1 = Complex(-10, 3)
c2 = Complex(1, -2)
self.assertEqual(str(c1.subtract(c2)), "-11.00 + 5.00i", "Should equal '-9.00 + 7.00i'")
