pycharm安装django-haystack 2.6.0 报错

在终端或pycharm里，安装django-haystack

pip install django-haystack==2.6.0

系统报错

distutils.errors.DistutilsError: Could not find suitable distribution for Requirement.parse('setuptools_scm')

解决办法：
安装django-haystack之前，先安装setuptools

pip install setuptools-scm

再执行安装django-haystack的操作。

如果以上方法还会报错，可以安装certifi，解决问题

pip install certifi==2017.7.27.1

原因：

So 3.5 is getting certificates from the OS and 3.6 is not. Pip itself works because we bundle our own certificates but setup_requires is handled by setuptools and it relies on the OS unless you install certifi.