Hi, I'm having issues importing models with the latest version.
The traceback is
```
Traceback (most recent call last):
File "vtuber_webcam.pyx", line 338, in init vtuber_webcam
File "vtuber_webcam.pyx", line 189, in vtuber_webcam.App.__init__
File "avatar.pyx", line 139, in plugins.avatar.VPlugin.create
File "cc.pyx", line 295, in plugins.avatar.CharacterController.attach
File "phys.pyx", line 66, in plugins.avatar.PhysicsCharacterController._attach_spring_bones
File "spring.pyx", line 340, in plugins.avatar.build_spring_chains
AttributeError: 'NoneType' object has no attribute 'get_x'
```
I'm having the issue with all the WRM models I have but the issue doesn't happen when using the xbot.wrm included model.