package DataDefs::Factory;
use strict;
use warnings;
# define data here in 'my' variables ...
my $hash_thing = {
   foo => 1,
   bar => 2,
   baz => 3,
};

# and so on

sub unshared_thing {
    # Called as a class method...
    my($class) = @_;

    # Make a copy of the data so that we'll not have
    # trouble elsewhere if the caller modifies it.
    my %copy = %{ $hash_thing };
    return \%copy;
}

1;

##</code><code>##

use DataDefs::Factory;

my $thingy = DataDefs::Factory->first_thing;

##</code><code>##

...
use Clone qw(clone);
...
sub first_thing {
    my($class) = @_;
    return clone($hash_thing);
}