Well, Perl does come with Time::Piece built-in these days.   Does yours?

If not, perhaps you could cabbage the source-code from the module that you would like to use, or at least the relevant parts of it, into a small class of your own making.   (Be sure to construct .t tests so that you can prove that it still works.   Cabbage tests from the module that you wanted to use, freely, but do run them.)   Even if you cannot, for whatever reason, invoke the very CPAN code-library that you want, at least you do not need to re-invent the algorithmic wheel.