#!/usr/bin/env perl
use 5.024;
use strict;
use warnings;
use experimental 'signatures';

package Foo {
    sub new($class,%attrs) { bless \%attrs,$class }
    sub thing($self,$value=return $self->{thing}) { $self->{thing} = $value }
};

my $foo = Foo->new(thing=>7);
say $foo->thing; # prints 7
$foo->thing(5);
say $foo->thing; # prints 5