              self.head = None
              self.tail = None
          else:
              self.head = self.head.next
          return data 
</s> remove         return self.peek() is None </s> add  </s> remove         assert_equal(sorted_stack.pop(), 1)
 </s> add         self.assertEqual(sorted_stack.pop(), 1) </s> remove         assert_equal(stack.pop(), 5)
        assert_equal(stack.peek(), None)
 </s> add         self.assertEqual(stack.pop(), 5)
        self.assertEqual(stack.peek(), None) </s> remove     test.test_pop_on_empty(num_stacks, stack_size)
    test.test_push_on_full(num_stacks, stack_size)
 </s> add     test.assertRaises(Exception, test.test_pop_on_empty, num_stacks,
                      stack_size)
    test.assertRaises(Exception, test.test_push_on_full, num_stacks,
                      stack_size) </s> remove     "        assert_equal(sorted_stack.pop(), 1)\n",
 </s> add     "        self.assertEqual(sorted_stack.pop(), 1)\n",
              self.head = None
              self.tail = None
          else:
              self.head = self.head.next

keep keep keep keep replace
 #273: Remove nose dependency for stacks_queues/ (#276) 
stacks_queues/queue_list/queue_list.py