TypeError: Invalid first argument to register()

[charterchap]

• Description of issue
  Using Python 3.7.0, Can not import niswitch (0.9.0 and 1.0.0)

import niswitch
C:\Program Files (x86)\Python37-32\lib\site-packages\niswitch\init.py:7: in
from niswitch.session import Session # noqa: F401
C:\Program Files (x86)\Python37-32\lib\site-packages\niswitch\session.py:7: in
import niswitch._attributes as _attributes
C:\Program Files (x86)\Python37-32\lib\site-packages\niswitch_attributes.py:3: in
import niswitch._converters as _converters
C:\Program Files (x86)\Python37-32\lib\site-packages\niswitch_converters.py:54: in
@_convert_repeated_capabilities.register(six.string_types) # noqa: F811
C:\Program Files (x86)\Python37-32\lib\functools.py:801: in register
f"Invalid first argument to register(): {cls!r}. "
E TypeError: Invalid first argument to register(): (<class 'str'>,). Use either @register(some_class) or plain @register on an annotated function.
!!!!!!!!!!!!!!!!!!! Interrupted: 1 errors during collection !!!!!!!!!!!!!!!!!!!
```

• Steps to reproduce issue

  import niswitch

This may be of interest:
python/cpython@e569753

[marcoskirsch]

1. Do you have numpy? I'm wondering if it is related to numpy 1.15.0rc1 breaks loading some DLLs #894
2. You mention niswitch only. Is that because that's the only module from nimi-python that you tried, or because it is the only one that broke? I'm wondering if it's something specific to niswitch or if the issue affects all modules.
3. Does this work on other Python versions, or have you not tried it? Wondering if it's an installation-specific problem.
4. Are you using a 64-bit or 32-bit Python?

[charterchap]

It does work fine with python 3.6.5. I do have numpy installed. niswitch is the first of the nimi-python imports, so i'm not sure if the others have the same problem (i've since downgraded python).
Take a look at the commit in the python code base from my original post. I think they changed something on you with @register.

[charterchap]

python/cpython#4733