Continue working on moving Challenge data preparation utilities to SIRF.

[evgueni-ovtchinnikov]

Changes in this pull request

Testing performed

Related issues

PR #1241

Checklist before requesting a review

• I have performed a self-review of my code
• I have added docstrings/doxygen in line with the guidance in the developer guide
• I have implemented unit tests that cover any new or modified functionality
• The code builds and runs on my machine
• CHANGES.md has been updated with any functionality change

Contribution Notes

Please read and adhere to the contribution guidelines.

Please tick the following:

• The content of this Pull Request (the Contribution) is intentionally submitted for inclusion in SIRF (the Work) under the terms and conditions of the Apache-2.0 License.

[KrisThielemans]

I won't have time to review this today, but I think you've addressed my main concerns, so go ahead when you're ready.

Given the tortuous history here, I suggest a squash-merge, but please edit the commit message such that it not just a list of all the attempts, but an overall conclusion. (Note that I see you're adding modality, which is great, so add that to the CHANGES.md).

thanks!

[KrisThielemans]

looks like you still need to remove examples/Python/PET/test_data_preparation.py