[Python] pip Import Error:cannot import name main

更新 pip 到 pip 10 以後會出現奇怪的訊息

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

看來只要修改 /usr/bin/pip，將

from pip import main
if __name__ == '__main__':
    sys.exit(main())

改為

from pip import __main__
if __name__ == '__main__':
    sys.exit(__main__._main())