Python AttributeError: ‘map‘ object has no attribute ‘extend‘

C:UserskaiDesktopCRC32-1-6位>python3 crc321-6.py
verification checksum: 0x308e1d5b (OK)
Traceback (most recent call last):
  File "C:UserskaiDesktopCRC32-1-6位crc321-6.py", line 3, in 
    crc32_reverse(0x308e1d5b,4)
  File "C:UserskaiDesktopCRC32-1-6位my_crc32.py", line 129, in crc32_reverse
    obj.run_reverse()
  File "C:UserskaiDesktopCRC32-1-6位my_crc32.py", line 109, in run_reverse
    patch.extend(last_4_bytes)
AttributeError: 'map' object has no attribute 'extend'

            for item in self.dfs(self.length - 4):
                patch = map(ord, item) ###Python 2.x 返回列表。
                patches = self.findReverse(desired, self.calc(patch, accum))
                for last_4_bytes in patches:
                    if all(p in self.char_set for p in last_4_bytes):
                        patch.extend(last_4_bytes)
                        print ('[find]: {1} ({0})'.format('OK' if self.calc(patch, accum) == desired else 'ERROR', ''.join(map(chr, patch))) )

这里就有一个问题，对于map()函数的用法，在python2和3中的有些许差别，也就导致无法后续继续调用计算：
map() 函数语法：
map(function, iterable, …)
参数
function – 函数
iterable – 一个或多个序列
返回值
Python 2.x 返回列表。
Python 3.x 返回迭代器。

所以需要把 patch = map(ord, item)修改成patch = list(map(ord, item) )

要把map函数返回的迭代器转换为列表（list），这就是由于python2，Python3版本不同偏差

            for item in self.dfs(self.length - 4):
                patch = list(map(ord, item) )###  map(ord, item),Python 3.x 返回迭代器。
                patches = self.findReverse(desired, self.calc(patch, accum))
                for last_4_bytes in patches:
                    if all(p in self.char_set for p in last_4_bytes):
                        patch.extend(last_4_bytes)
                        print ('[find]: {1} ({0})'.format('OK' if self.calc(patch, accum) == desired else 'ERROR', ''.join(map(chr, patch))) )