pip出现问题

错误：

Traceback (most recent call last):
  File "/usr/bin/pip", line 9, in <module>
    from pip import main
ImportError: cannot import name 'main'

修改

/usr/bin/pip
为如下：

#!/usr/bin/python

# -*- coding: utf-8 -*-
import re
import sys

from pip import __main__
from pip._internal import main

if __name__ == '__main__':
    sys.argv[0] = re.sub(r'(-script\.pyw|\.exe)?$', '', sys.argv[0])
    sys.exit(__main__._main())