#if the type is NoneType,the isinstance does not work
#we should judge the NoneType like below
#if row is None
#if type(row) is types.NoneType
#In my opinion,use the types to judge the type of a param is convinient<SPANstyle="BACKGROUND-COLOR: rgb(255,255,255); FONT-FAMILY: Arial">, use the isinstance to judge whether a instance is a type of a class or not</SPAN>