Fix tutorial: rename attr to urwid_attr

[penguinolog]

Prevent stdlib attr shadowing in case of sys.path altered

Fix: #649

Checklist

• I've ensured that similar functionality has not already been implemented
• I've ensured that similar functionality has not earlier been proposed and declined
• I've branched off the master or python-dual-support branch
• I've merged fresh upstream into my branch recently
• I've ran tox successfully in local environment
• I've included docstrings and/or documentation and/or examples for my code (if this is a new feature)

[penguinolog]

@ulidtko without this PR changes, full regeneration of images in documentation is impossible :-(

[wardi]

interesting, is there something special about the name attr?

[penguinolog]

interesting, is there something special about the name attr?

I mixed in my memory dataclasses with "attrs" package.
attr is a part of attrs package, it is extremely common library for cases, where dataclasses are not available or not enough functional.
You define like

import attr

@attr.s
class Config:
    a: dict[str, int] = attr.ib(factory=dict, ...

And other code is generated

[wardi]

so this change isn't actually required then

[penguinolog]

so this change isn't actually required then

Scripts location is added to sys.path at first position, then during imports modules lookup uses sys.path. Anything using attr is broken and it's one of our dependencies, which call some logic on import

[wardi]

the docs/tutorial directory isn't added to sys.path and these are scripts not modules to be imported, right?

[penguinolog]

the docs/tutorial directory isn't added to sys.path and these are scripts not modules to be imported, right?

It's added automatically on run as script.
Short example

alekseis@1857be7-lcelt ~/tmp $ batcat *          
───────┬──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
       │ File: logging.py
───────┼──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
   1   │ print("this should not be executed")
───────┴──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
───────┬──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
       │ File: tst.py
───────┼──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
   1   │ import logging
   2   │ import sys
   3   │ 
   4   │ print(sys.path)
   5   │ 
   6   │ logging.basicConfig(level=logging.INFO)
   7   │ logger = logging.getLogger(__name__)
   8   │ logger.info("it works")
───────┴──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
alekseis@1857be7-lcelt ~/tmp $ python tst.py     
this should not be executed
['/home/alekseis/tmp', '/usr/lib/python311.zip', '/usr/lib/python3.11', '/usr/lib/python3.11/lib-dynload', '/usr/local/lib/python3.11/dist-packages', '/usr/lib/python3/dist-packages', '/usr/lib/python3.11/dist-packages']
Traceback (most recent call last):
  File "/home/alekseis/tmp/tst.py", line 6, in <module>
    logging.basicConfig(level=logging.INFO)
    ^^^^^^^^^^^^^^^^^^^
AttributeError: module 'logging' has no attribute 'basicConfig'

As you can see, sys.path was altered and instead of normal logging, another code was imported