Install any package by marking below hosts trusted
- pypi.python.org
- pypi.org
- files.pythonhosted.org
临时的解决方法：
pip install --trusted-host pypi.python.org --trusted-host pypi.org --trusted-host files.pythonhosted.org {package name}
永久的解决方法：
Update your PIP(problem with version 9.0.1) to latest：更新到最新版本的pip
1、
pip install --trusted-host pypi.python.org --trusted-host pypi.org --trusted-host files.pythonhosted.org pytest-xdist
2、
python -m pip install --trusted-host pypi.python.org --trusted-host pypi.org --trusted-host files.pythonhosted.org --upgrade pip
下载pip地址：