Suggestion: In case the failing expression is known to lawfully consult with something that's from time to time null or missing, possibly specify a default worth like myOptionalVar!师傅进门会穿鞋套，工作台面会铺上厚厚的塑料膜。临走收拾的干干净净。油烟机也擦的锃亮！自助服务 产品服务政策 专享权�