Не работает pyknow

Импортировал библиотеки для ИИ:

import pyknow.pyknow
from pyknow import *

При запуске программы выдаёт ошибки:

from pyknow import abstract
ImportError: cannot import name 'abstract' from 'pyknow' (unknown location

Версия питона 3.8. Что делать? Полный стек:

C:\Users\Tagir\PycharmProjects\ClassificationLab2\venv\Scripts\python.exe C:\Users\Tagir\PycharmProjects\ExpertSystemLab1\main.py 
Traceback (most recent call last):
  File "C:\Users\Tagir\PycharmProjects\ExpertSystemLab1\main.py", line 3, in <module>
    import pyknow.pyknow
  File "C:\Users\Tagir\AppData\Local\Programs\Python\Python38\pyknow\pyknow\__init__.py", line 2, in <module>
    from .engine import KnowledgeEngine
  File "C:\Users\Tagir\AppData\Local\Programs\Python\Python38\pyknow\pyknow\engine.py", line 10, in <module>
    from pyknow import abstract
ImportError: cannot import name 'abstract' from 'pyknow' (unknown location)
Process finished with exit code 1

Если убрать import pyknow.pyknow:

Traceback (most recent call last):
  File "C:\Users\Tagir\PycharmProjects\ExpertSystemLab1\main.py", line 11, in <module>
    class CanFly(Fact):
NameError: name 'Fact' is not defined

Process finished with exit code 1