(maint) Remove unneeded parens around exceptions
(maint) Explicitly unpack validate_slength args
(maint) reword error messages for validate_slength
(maint) clean up validate_slength argument validation
(maint) collapse String/Array validation into shared lambda
(maint) reindent case statement to match standard indentation
(maint) refactor validate_slength tests
(maint) Validate input argument in a single location
Merge branch 'maint-refactor_validate_slength'