Remove some print statements within algorithmic functions (#7499)

* Remove commented-out print statements in algorithmic functions

* Encapsulate non-algorithmic code in __main__

* Remove unused print_matrix function

* Remove print statement in __init__

* Remove print statement from doctest

* Encapsulate non-algorithmic code in __main__

* Modify algorithm to return instead of print

* Encapsulate non-algorithmic code in __main__

* Refactor data_safety_checker to return instead of print

* updating DIRECTORY.md

* updating DIRECTORY.md

* Apply suggestions from code review

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
Co-authored-by: Christian Clauss <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>