Emacs Lisp:如何对列表中的奇数求和？

(defun sum-odd-numbers (numbers)
  (let ((sum 0))
    (dolist (number numbers)
      (if (oddp number)
          (setq sum (+ sum number))))
    sum))

(setq numbers '(1 2 3 4 5 6 7 8 9))

(sum-odd-numbers numbers)