Fix possibly-used-before-assignment pylint errors (CI failing on master for pylint)

Description of the changes

Close #128 (closed)

I believe most of the problems reported by pylint are false positives. It looks like the new check/feature is buggy as there are already 5 issues reported in the last two days: https://github.com/pylint-dev/pylint/issues?q=is%3Aissue+is%3Aopen+possibly-used-before-assignment+

I decided to waive some of them and address others.

Check-list

• Make sure that a changelog entry is present
• Label the MR according to the content
• If this MR has a dependency on another MR, specify the order in which the MRs should be merged
• If the MR is done, please mark it as such by using the ~"Done - awaits merge" label, else mark it as "Draft: " by adding the prefix to the title
• Designate a reviewer for this MR once done
• Update the supported features and limitations here

Reviewer check-list

• Make sure that the title describes the changes in the merge request
• Make sure that the description of the changes is relevant and it describes all the changes
• Make sure that the changelog entry is consistent with the changes. If the first release on top was released, then make sure that a new running release is created incrementing the minor index (the version is in the format major.minor.patch)