Add revalidate_fn optional param to cached_result for additional check if cache should be revalidated

[tjeerddie]

• revalidate_fn: Callable function that returns bool whether to revalidate the cached result.
• update unit tests.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.63%. Comparing base (2a8a97e) to head (a4648f3).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #44      +/-   ##
==========================================
+ Coverage   80.51%   80.63%   +0.12%     
==========================================
  Files          13       13              
  Lines         467      470       +3     
  Branches       62       63       +1     
==========================================
+ Hits          376      379       +3     
  Misses         71       71              
  Partials       20       20              

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[Mark90]

LGTM, small nit in testcode