python 3 哈希验证文件 验证文件的sha 256

import hashlib
import os
import sys

def sha256(filename, onlyname):
    f = open(filename, 'rb')
    sh = hashlib.sha256()
    sh.update(f.read())
    print (sh.hexdigest(),"*",onlyname )
    f.close()
    return

path =  sys.path[0]
print(path)
list1=os.listdir(path)
print(path + list1[4])

for i in range(0,len(list1)):
    if (os.path.isfile(path + '//' + list1[i]) == True ):
        sha256(path + '//' + list1[i], list1[i])