Python 3.7.4 macOS 10.14.5 (homebrew) 

According to https://docs.python.org/3/library/os.html#os.cpu_count , there is a method `os.sched_getaffinity()` (https://docs.python.org/3/library/os.html#os.sched_getaffinity)

Code to reproduce :
 - 
```
import os
len(os.sched_getaffinity(0))
```


Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: module 'os' has no attribute 'sched_getaffinity'

Per the docs on the function group that includes os.sched_getaffinity ( https://docs.python.org/3/library/os.html#interface-to-the-scheduler ):

> These functions control how a process is allocated CPU time by the operating system. They are only available on some Unix platforms. For more detailed information, consult your Unix manpages.

> New in version 3.3.

> The following scheduling policies are exposed if they are supported by the operating system.

OSX doesn't support these APIs, so Python on OSX won't have them.