扩展包安装问题：module 'pip' has no attribute 'main'

找到安装目录下 helpers/packaging_tool.py文件，找到如下代码：

def do_install(pkgs):
try:
import pip
except ImportError:
error_no_pip()
return pip.main(['install'] + pkgs)

def do_uninstall(pkgs):
try:
import pip
except ImportError:
error_no_pip()
return pip.main(['uninstall', '-y'] + pkgs)

修改为如下，保存即可。

def do_install(pkgs):
try:
# import pip
try:
from pip._internal import main
except Exception:
from pip import main
except ImportError:
error_no_pip()
return main(['install'] + pkgs)

def do_uninstall(pkgs):
try:
# import pip
try:
from pip._internal import main
except Exception:
from pip import main
except ImportError:
error_no_pip()
return main(['uninstall', '-y'] + pkgs)