anchor.diff:        (who-sets-using-metasheep (sheep-metasheep sheep) sheep property-name)))
   (defun std-who-sets (sheep property-name)
     (multiple-value-bind (owner has-p)
  -      (gethash property-name (sheep-property-owners sheep))
  +      (gethash property-name (gethash 'property-owners sheep))
       (if has-p
   	owner
   	(error 'unbound-property))))
  
positive.code:     (setf (gethash 'property-owners object) (make-weak-hash-table :weakness :value :test #'equal))
      (setf (gethash 'roles object) nil)
      (setf (gethash 'hierarchy-list object) nil)
      (std-finalize-sheep object)
      object))
  
  (defvar =t=
    (let ((obj (std-generate-sheep-instance =standard-sheep-metasheep=)))
      (setf (gethash 'nickname obj) "=t=")
  
negative.code: 
  ;;; Inheritance predicates
  (defun direct-parent-p (maybe-parent child)
    (when (member maybe-parent (gethash 'parents child))
      t))
  
  (defun ancestor-p (maybe-ancestor descendant)
  