anchor.diff:  
                (hash-table
                 (restore-flat-history history path))))
  -          (_ (error "Expected (list version history) structure.")))))))
  +          (_ (progn
  +               (error "Expected (list version history) structure.")
  +               nil)))))))
   
   
   (defun histories-list (&optional (buffer (current-buffer)))
  
positive.code:                    (expand-path path))
               (setf (get-data path) history)
               (when restore-buffers-p
                 (restore-buffers history)))
  
             (restore-flat-history (old-history old-path)
               (echo "Importing deprecated global history of ~a URLs from ~s."
  
negative.code:                             ;; twice.
                              (setf (last-access data) "")
                              (htree:add-entry history data last-access)))
                          old-history)
                 history)))
      (with-muffled-body ("Failed to restore history from ~a: ~a"
                          (expand-path path) :condition)
        (let* ((path (if (uiop:file-exists-p (expand-path path))
  