If you don't want your internal modules/subs being used by external code, you can catch that.

Abide by the ethos?

Why assume you're smart enough to know what your users are paying for today/tomorrow?

This is all the checks you need

=head1 FOR INTERNAL USE ONLY

This is private api for internal use only, it can change at any time, 
+standard disclaimers apply, use at your own risk....

=cut
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