A.(date1-date2).daysB.date1.diff(date2)C.date.days_between(date1,date2)D.date1-date2
A.list =[[1,2],[3,4]]B.list =array([1,2],[3,4])C.list =2D([1,2],[3,4])D.list =Matrix([1,2],[3,4])
A.isinstance(var,str)B.type(var)is strC.var.isString()D.A和B都对