[Custom Issue]: post Processing Code Maintenance

### Contact Details

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### Are there any linked Issues or Pull Requests?

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### Brief description

Maintenance of the new post processing python module would benefit from targeted code linting, e.g. pylint, run in the CI pipeline.

i have not done this within #223 as this would make the changes hard to distinguish

hence this follow up issue:

Scope:
* establish linting in CI
* fix source to pass linting

### Further details of the issue.

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Locate the new post-processing Python module and the repository's CI configuration first. Establish a linting step in CI, then use its findings to guide the source cleanup. Done means the linting job runs in CI and the post-processing source passes it.

Written by the indexing model from the issue text.