Hello SimonPratt and thank you for stopping by. I have a few specific questions about the code you provided. I will be writing up something more general as a reply to my OP to show the true breadth of the module.

1. Is Perl 5.16.2 required? I write for 5.8.8 since that is what my web host provides.
2. How are you getting %movies_data from the module to the script below?

   #!/usr/bin/perl
   use strict;
   use warnings;
   
   # movie is the first package name I found in the module, 
   # so I'm guessing it is also the module's name.
   use movie;
   
   
   my $library = library->new(name => "Lucky's");
   foreach my $movie (values %movies_data) {
       $library->add_movie(movie->new(%$movie));
   }
   
   $library->print();
   [download]

   I see %movies_data but I don't see how you got it from the module. %movies_data is not something I want to have to copy and paste to the three scripts which use it now.
3. Why doesn't end_year get a value if it does not have one? It needs an end year for run_time which you seem to have dropped.

You do not need to worry about adding movies with this module. I enter the data into the file by hand since the last time I did anything with the data file with a script, I accidentally dropped a value causing me to have to redo my research for the value for a lot of movies.

The module I am possibly rewriting has 7 hashes, 5 of which get sent out to scripts from the module. Some values of the hashes use the subroutines and other hashes to create some of the values. It is a big complex organism.