def test_equals(self):
     self.assertEqual(nb_year(1500, 5, 100, 5000), 15)
 def test_equals_2(self):
     self.assertEqual(nb_year(1500000, 2.5, 10000, 2000000), 10)
 def test_equals_3(self):
     self.assertEqual(nb_year(1500000, 0.25, 1000, 2000000), 94)