Org mode: parse week with customizable start of week number

parse-week.el

(with-eval-after-load 'org
    (setq start-week 37)
    (advice-add 'org-read-date-analyze :around
      (lambda (original-fun ans org-def org-defdecode)
        (funcall original-fun
                  (if (string-match "^s\\([0-9]+\\)\\(.*\\)" ans)
                      (concat "w"
                              (number-to-string (+ start-week
                                                   (string-to-number (match-string 1 ans))))
                              (match-string 2 ans))
                    ans)
                  org-def org-defdecode)))
    ))