anchor.diff:  
     Example: 
   
  -  ``(choose-many \"Choose: \" (list \"foo\" \"bar\" \"baz\") :default \"baz\")``
  -
  -  Tags: menu, choose" 
  +  ``(choose-many \"Choose: \" (list \"foo\" \"bar\" \"baz\") :default '(\"baz\"))``
  +
  +  Tags: menu, choose"
  +  (assert (every (lambda (option) (member option options :test 'string=)) default)
  +	  nil "Invalid default: ~s" default)
     (let ((chosen-options nil))
       (flet ((print-options ()
   	     (loop 
  
positive.code: 	(loop 
  	   do 
  	     (cond ((equalp chosen-option "")
  		    (if default
  			(return default)
  			(return (reverse chosen-options))))
  		   ((find chosen-option (mapcar #'princ-to-string options) :test #'string=)
  		    (pushnew (find chosen-option (mapcar #'princ-to-string options) :test #'string=) chosen-options :test test)
  		    (when print-options
  
negative.code: 
    ``(choose \"Choose: \" (list \"foo\" \"bar\" \"baz\") :default \"baz\")``
  
    Tags: menu, choose"
    (assert (or (not default)
  	      (member default options :test 'string=))
  	  nil "Invalid default: ~s" default)
    (flet ((print-options ()
  	   (loop 
  	      for option in options
  