I am trying to import a specific class variable from another file in Python 3. However, I am not sure how to do this corretly or even make it to work at all. 

File "gui.py"

```py
class Gui:
    def __init__(self):
        self.board = [0]

    def run(self):
        self.board = [2]

if __name__ == '__main__':
    Gui().run()

```

In file eval.py below I want to use the updated variable self.board = [2] from gui.py. I tried below code examples but got the error "AttributeError: type object 'Gui' has no attribute 'board'" in both cases.

File "eval.py"

```py
from gui import Gui

board = Gui.board

```

```py
board = __import__('gui').Gui.board

```

I also tried to remove the name=main thing from gui.py but as expected it only made gui.py run its code and then I got the same error as previously. 

How do I access the variable self.board from Gui.run() from gui.py in eval.py in the best and most efficient possible way?