taobao.fenxiao.product.update 更新产品
        
        - 更新分销平台产品数据，不传更新数据返回失败
        - 对sku进行增、删操作时，原有的sku_ids字段会被忽略，请使用sku_properties和sku_properties_del。

def update(self, pid, session, **kwargs):
        '''taobao.fenxiao.product.update 更新产品
        
        - 更新分销平台产品数据，不传更新数据返回失败
        - 对sku进行增、删操作时，原有的sku_ids字段会被忽略，请使用sku_properties和sku_properties_del。'''
        request = TOPRequest('taobao.fenxiao.product.update')
        request['pid'] = pid
        for k, v in kwargs.iteritems():
            if k not in ('name', 'standard_price', 'cost_price', 'retail_price_low', 'retail_price_high', 'outer_id', 'quantity', 'alarm_number','desc','prov','city','postage_type','postage_id','postage_ordinary','postage_fast','postage_ems','status','sku_ids','sku_cost_prices','sku_quantitys','sku_outer_ids','have_invoice','have_guarantee','discount_id','sku_standard_prices','sku_properties','sku_properties_del','is_authz','pic_path','image','properties','property_alias','input_properties','dealer_cost_price','sku_dealer_cost_prices','category_id') and v==None: continue
            request[k] = v
        self.create(self.execute(request, session), fields=['pid','modified'], models={'modified':TOPDate})
        return self