```common lisp
(cl:in-package #:clump-test)

```

Define subclasses of 2-3 tree classes for testing purposes.
user
```common lisp
(cl:in-package #:clump-test)

(defclass size-mixin ()
  ((%size :initarg :size :reader size)))

(defclass leaf-size (size-mixin clump-2-3-tree:leaf)
  ()
  (:default-initargs :size 1))

(defclass 2-node-size (size-mixin clump-2-3-tree:2-node)
  ())

(defclass 3-node-size (size-mixin clump-2-3-tree:3-node)
  ())

(defclass size-tree (clump-2-3-tree:tree)
  ()
  (:default-initargs
   :2-node-class '2-node-size
   :3-node-class '3-node-size))
```
assistant