Holidays module files

[Eschay]

Hi! I started learning module coding with an example module "Holidays" of an apparently good guide book, "Introduction to Writing Modules for CMS Made Simple". I got stuck however quite soon with an error message.

Fatal error: Cannot redeclare Holidays::VisibleToAdminUser() in C:\xampp\htdocs\sjkl\modules\Holidays\Holidays.module.php on line 15

My question is, are the complete, working files of the Holidays module available somewhere online? It might be the easiest way to see what's wrong.