Phatom pyvsystems.error module

[sunnyking]

Not sure why could do:

from pyvsystems.error import InvalidAddressException

But the exception module is supposedly:

from pyvsystems.errors import InvalidAddressException

Importing as former gets no complaint but try block would not catch the said exception.

[sunnyking]

Tested on 0.2.0 and confirmed this behavior.

[sunnyking]

This problem appears more serious than I thought.
On android, gemmer crashes with

ModuleNotFoundError: No module named 'pyvsystems.errors'

In ubuntu pipenv, the pyvsystems package 0.2.0 has both error.py and errors.py

[sunnyking]

Gemmer has to revert to pyvsystems 0.1.0 for now until fix is available.