Account for whitespace-only separation of flake8 error selectors/ignores

[PeterJCLaw]

It appears that flake8 allows for ignored errors in an ignore section to be whitespace separated, without the need for commas. Autopep8 however doesn't seem to allow for this -- configs which only have whitespace separation result in none of the requested error types being ignored, nor an error about invalid config.

Python Code

print("foo")
import os  # E402

Command Line and Configuration

[flake8]
ignore =
    C401
    E402

Command Line

$ autopep8

Your Environment

• Python version: 3.9.18
• autopep8 version: autopep8 2.0.4 (pycodestyle: 2.11.0)
• Platform: Ubuntu 22.04.3 LTS