如何用python检查函数参数是否合格？

def scoreCalculate(values):

    #判断参数必须为列表，否则直接返回

    if not isinstance(values,list):

        print("values is not list, return")

        return

    print("start Calculate:")

    return max(values), min(values), sum(values)/len(values)

maxval = scoreCalculate('')

print(maxval)

values is not list, return

None