anchor.diff:  (defun rassoc-test-not-key (item alist test key)
     (loop for element in alist
           when (and (not (null element))
  -		  (not (funcall test (funcall key (cdr element)) item)))
  +		  (not (funcall test item (funcall key (cdr element)))))
             return element))
     
   (defun rassoc (item alist &key key test test-not)
  
positive.code: (defun rassoc-eq-key (item alist key)
    (loop for element in alist
          when (and (not (null element))
  		  (eq (funcall key (cdr element)) item))
            return element))
    
  ;;; Special version when test is eql and key is given.
  
negative.code: (defun rassoc-test-not-identity (item alist test)
    (loop for element in alist
          when (and (not (null element))
  		  (not (funcall test item (cdr element))))
            return element))
  
  ;;; Special version when test-not and key are both given.
  