python3.6 ImportWarning: can't resolve package from __spec__ or __package__, falling back on __name__ and __path__

Cython emulates Python 2-style implicit relative imports on Python 3

Cython的锅（也就是绝大多数下载安装的python）新的import机制，把py3当成py2来处理了。

Python actually does the same thing. When you run code in Python 2, it uses the Python 2 parser and generates Python 2 byte code. If you run it in Python 3, it uses a Python 3 parser and generates Python 3 byte code. 

——转义成C代码的时候，会根据是py3还是py2的语法来转（即使你安装的是py3的安装包）。这TM是纯坑啊！

https://github.com/cython/cython/issues/1720#issuecomment-304590138

要么在每个文件开头加入

from __future__ import absolute_import

要么

-from . import _ufuncs
+from scipy.special import _ufuncs