not what you asked for but... you may want to make your instantiation of copy books more flexible. perhaps add a method to Product::Datafile that takes in an array of filter codes

sub createCopybooks
{
    my $self = shift;
    my @filterCodes = @_;
    
    my %copyBooks;
    foreach my $filterCode ( @filterCodes )
    {
        my $copyBook              = Cobol::Copybook->new({filehandle =
+> \*DATA, filter => $filterCode} );
        my $copyBookName          = 'cpy' . $filterCode;
        $copyBooks{$copyBookName} = $copyBook;
    }
    
    $self->{copybooks} = \%copyBooks;
}
[download]

then you can easily change how many copybooks you want like so:

$productDatafile->createCopybooks('00', '01', '04', '42', '99');
[download]

hth!