有时安装的pip版本过低，用pip安装软件时会报python

pip._vendor.distlib.DistlibException: Unable to locate finder for 'pip._vendor.distlib'

这时须要卸载掉pip setuptools，从新安装下bootstrap

1. uninstall current pip:spa

   python -m pip uninstall pip setuptools

2. download get-pip.py from https://bootstrap.pypa.io/get-pip.pycode

3. execute get-pip script:ip

   python get-pip.py

4. virtualenv新建的直接python get-pip.py就能够 --！