输入pip命令报错：from pip import main ImportError: cannot import name 'main'

执行pip命令报错： 

$ pip3 -V
Traceback (most recent call last):
  File "/usr/bin/pip3", line 9, in <module>
    from pip import main
ImportError: cannot import name 'main'

解决办法：

sudo gedit /usr/bin/pip3

/修改前
from pip import main  
if __name__ == '__main__':  
    sys.exit(main()) 
修改后
from pip import __main__  //这行也要修改
if __name__ == '__main__':  
    sys.exit(__main__._main())//增加__main__._

结果： 

$ pip3 -V
pip 19.3.1 from /home/biny/.local/lib/python3.5/site-packages/pip (python 3.5)