woocommerce_enable_coupon_form_on_cart is not implemented

Just want to let the developer know the the option: woocommerce_enable_coupon_form_on_cart defined in cart/cart.php is not defined anywhere, which means even if I check the box of allowing use of coupon, the form on cart page will still not show.

Please implement it and release on the next release.

Thank you.

http://wordpress.org/extend/plugins/woocommerce/