Move save_hyperparameters to its own function

[tchaton]

What does this PR do?

Motivation

Would like to add save_hyperparemeters to Flash Preprocess / Postprocess, so we don't pickle the object.

Before submitting

• Was this discussed/approved via a GitHub issue? (not for typos and docs)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure your PR does only one thing, instead of bundling different changes together?
• Did you make sure to update the documentation with your changes? (if necessary)
• Did you write any new necessary tests? (not for typos and docs)
• Did you verify new and existing tests pass locally with your changes?
• Did you update the CHANGELOG? (not for typos, docs, test updates, or internal minor changes/refactorings)

PR review

Anyone in the community is free to review the PR once the tests have passed.
Before you start reviewing make sure you have read Review guidelines. In short, see the following bullet-list:

• Is this pull request ready for review? (if not, please submit in draft mode)
• Check that all items from Before submitting are resolved
• Make sure the title is self-explanatory and the description concisely explains the PR
• Add labels and milestones (and optionally projects) to the PR so it can be classified

Did you have fun?

Make sure you had fun coding 🙃

[codecov]

Codecov Report

Merging #7119 (26ae30f) into master (0302b8b) will decrease coverage by 0%.
The diff coverage is 97%.

@@           Coverage Diff           @@
##           master   #7119    +/-   ##
=======================================
- Coverage      92%     92%    -0%     
=======================================
  Files         197     197            
  Lines       12645   12769   +124     
=======================================
+ Hits        11661   11733    +72     
- Misses        984    1036    +52     

[carmocca]

What motivates this change? Just reorganizing?

[tchaton]

What motivates this change? Just reorganizing?

Hey @carmocca, I would like to add save_hyperparemeters to Flash Preprocess / Postprocess, so we don't pickle the object. I needed the function to be extracted and merged in the next rc.

Best,
T.C