use strict;
use warnings;

use MyMod;
my $mm = MyMod->new(atr1 => 1, atr2 => 'string2');

print $mm->get('atr1')."\n";
print $mm->get('atr2')."\n";
$mm->set('atr1', 42);
print $mm->get('atr1')."\n";

$mm->{atr1} = 3000;    <<<<---- Fails "Not a HASH reference"