taobao.fenxiao.product.sku.update 产品sku编辑接口
        
        产品SKU信息更新

def sku_update(self, product_id, properties, session, **kwargs):
        '''taobao.fenxiao.product.sku.update 产品sku编辑接口
        
        产品SKU信息更新'''
        request = TOPRequest('taobao.fenxiao.product.sku.update')
        request['product_id'] = product_id
        request['properties'] = properties
        for k, v in kwargs.iteritems():
            if k not in ('quantity', 'standard_price', 'agent_cost_price', 'sku_number', 'dealer_cost_price') and v==None: continue
            request[k] = v
        self.create(self.execute(request, session), fields=['result','created'], models={'created':TOPDate})
        return self