code: function (coupon, cb) {
  
  		Coupon.destroy(coupon.id)
  	    .exec(function (err, destroyedCoupons){
  	      if (err) return cb(err);
  	      if(!destroyedCoupons) return cb(null, null);
  	      Coupon.afterStripeCouponDeleted(destroyedCoupons[0], function(err, coupon){
  	      	cb(null, coupon);
  	      });
  	    });
  	}
docs: Stripe Webhook coupon.deleted