Fix a traceback in multiprocessing example

[serhiy-storchaka]

The multiprocessing module documentation contains the following example:

      >>> from multiprocessing import Pool
      >>> p = Pool(5)
      >>> def f(x):
      ...     return x*x
      ...
      >>> with p:
      ...   p.map(f, [1,2,3])
      Process PoolWorker-1:
      Process PoolWorker-2:
      Process PoolWorker-3:
      Traceback (most recent call last):
      Traceback (most recent call last):
      Traceback (most recent call last):
      AttributeError: 'module' object has no attribute 'f'
      AttributeError: 'module' object has no attribute 'f'
      AttributeError: 'module' object has no attribute 'f'

Actually, it is outdated. It was so in Python 2, but in Python 3 before 3.12 you get AttributeError with different message

AttributeError: Can't get attribute 'f' on <module '__main__' (built-in)>

and in 3.12 you get

AttributeError: Can't get attribute 'f' on <module '__main__' (<class '_frozen_importlib.BuiltinImporter'>)>

Linked PRs

• gh-100408: Fix a traceback in multiprocessing example #100409
• [3.11] gh-100408: Fix a traceback in multiprocessing example (GH-100409) #103275
• [3.11] gh-100408: Fix a traceback in multiprocessing example (GH-100409) #106231

[erlend-aasland]

It seems to me we can close this issue as completed.

[serhiy-storchaka]

The fix was not backported to 3.11 yet.