package MyMod;
    
use strict;
use warnings;
use Carp;
use Hash::Util::FieldHash qw[fieldhash];
    
fieldhash my %attr1;
fieldhash my %attr2;
 
my %hashrefs = (
    attr1 => \%attr1,
    attr2 => \%attr2,
);
        
sub new {
    my $class = shift;
    my %args = @_;
     
    my $self = bless do {\my $dummy}, $class;

    $attr1{$self} = $args{attr1};
    $attr2{$self} = $args{attr2};
    
    $self;
}
    
sub set {
    my ($self, $attr, $value) = @_;
    if (exists $hashrefs{$attr}) {
        $hashrefs{$attr}{$self} = $value
    }
    else {
        carp "Invalid attribute name $attr";
    }
}

sub get {
    my ($self, $attr) = @_;
    if (exists $hashrefs{$attr}) {
        return $hashrefs{$attr}{$self}
    }
    else {
        carp "Invalid attribute name $attr";
        return;
    }
}       

1;