python怎么判断是否为纯字母？

info = "gfhajsh136ju879kdi"

for i in info:

    if i.isalpha():

        info = info.replace(i," ")#若为字母，使用空格代替

l = info.split()

if len(l)>0:

    print('不是纯字母')

else:

    print('是纯字母')