读写tar存档文件
tarfile.open()
Signature: tarfile.open(name=None, mode=‘r’, fileobj=None, bufsize=10240, **kwargs)
打开tar存档进行读、写或追加
返回一个合适的TarFile类
import os
import tarfile
import urllib
import urllib.request
DOWNLOAD_ROOT = https://raw.githubusercontent.com/ageron/handson-ml2/master/
HOUSING_PATH = os.p
