perl -we'use strict; my $foo=Data::Vars->new();'
Can't locate object method "new" via package "Data::Vars" (perhaps you forgot to load "Data::Vars"?) at -e line 1.
> grep 'sub.*new' lib/Data/Vars.pm
        sub new (;$) {    # return blessed objects and init pre-defined fields w/args

##</code><code>##

#!/usr/bin/perl -w

use strict;
use warnings;
use IO::Dir;
my $dh=bless {}, 'IO::Dir::pl';
#my $dh = IO::Dir::pl->new('.');
while (my $file_name = $dh->read()){
    print STDOUT "$file_name\n";
    exit;
}


{
  package IO::Dir::pl;
  use strict; use warnings;
  our @ISA;
  @ISA = qw(IO::Dir);

  sub read{
    my $self = shift;
    warn "Ok We got here.\n";
    return undef;
  }
}

> /tmp/p
Ok We got here.
        (in cleanup) Not a GLOB reference at /usr/lib/perl5/5.16.2/x86_64-linux-thread-multi/IO/Dir.pm line 43.

##</code><code>##

#!/usr/bin/perl -w

{
  package IO::Dir::pl;
  use strict; use warnings;
  our @ISA;
  @ISA = qw(IO::Dir);

  sub read{
    my $self = shift;
    warn "Ok We got here.\n";
    return undef;
  }
}

use strict;
use warnings;
use IO::Dir;
my $dh = IO::Dir::pl->new('.');
while (my $file_name = $dh->read()){
    print STDOUT "$file_name\n";
    exit;
}

> /tmp/p
Ok We got here.