__import__ called with illegal value of level

[TonyKaap]

import is being called from load() in uitypes.py with a value of level=-1 . This is causing Attribute Editor failures in py3 versions of Maya.

Changed in version 3.3: Negative values for level are no longer supported (which also changes the default value to 0).
https://docs.python.org/3/library/functions.html#import__

https://github.com/LumaPictures/pymel/blob/5fbe189fc0e0e1fdf056be2dd2ae63d26ca33ed5/pymel/core/uitypes.py#L3910