Make uxsdcxx.py pep8 clean

[mithro]

Make all your Python code "pep8 clean". Running pep8 on your code should produce no errors.

• https://pep8.org/
• Black is an auto formatter that might be useful - https://black.readthedocs.io/en/stable/
• yapf is another auto formatter that is an alternative - https://github.com/google/yapf