def test_number_only_with_zeros(self):
     self.assertEqual(count_zeros(00000), 1)
 def test_one_zero(self):
     self.assertEqual(count_zeros(101), 1)
 def test_multiple_zeros(self):
     self.assertEqual(count_zeros(100010), 4)
 def test_no_zeros(self):
     self.assertEqual(count_zeros(11), 0)