anchor.diff:  properly. Immutable."
     (let* ((err (loop for (yi . xi) in cases
   		 for w across weights
  -		   if (= yi (funcall h xi))
  +		 if (not (= yi (funcall h xi)))
   		   summing w))
   	 (edited-weights 
   	  (map 'vector 
  
positive.code: (defun normalize (w-arr)
    "Destructively normalizes an array."
    (let ((sum (sum w-arr)))
      (map-into w-arr #'(lambda (x) (/ x sum)) w-arr)))
  
  (defun weighted-majority-fn (h z)
    "Returns a weighted majority function which will classify an attribute list."
  
negative.code: 		    (update-weights h-fn cases w)
  		    (setf w w+
  			  (svref h k) h-fn
  			  (svref z k) (log (max EPSILON 
  					    (/ (- 1 h-err)
  					       (max h-err EPSILON)))
  					   2))
  		    (incf k)))))
      (cons h z)))
  