code: def big_file(filename):
          
          
          md5 = hashlib.md5()
          with open(filename, 'rb') as f:
              for chunk in iter(lambda: f.read(8192), b''):
                  md5.update(chunk)
          
          result = md5.hexdigest()
          return result
docs: 获取一个大文件的 MD5 值
  
          :param:
              * filename: (string) 需要进行 hash 的大文件路径
          :return:
              * result: (string) 32位小写 MD5 值