(defun update-post (post &key (title nil title-supplied-p)
                              (path nil path-supplied-p))
  (let ((errors '()))
    (progn
      (when title-supplied-p
          (if (post-title-p title)
              (setf (slot-value post 'title) title)
              (setf errors (acons 'title "Invalid title" errors))))
      (when path-supplied-p
          (if (post-path-p path)
              (setf (slot-value post 'path) path)
              (setf errors (acons 'path "Invalid path" errors))))
      (if (equal errors '())
          (handler-case (mito:save-dao post)
            (t (c)
              (format t "Caught condition: ~A" c)
              (values nil '(( update_failure . "Persisting changes to DB failed")))))
          (values nil errors))
      (values t '()))))