#!/usr/bin/perl -w
use strict;
use Player;
use Hand;
#...
my @pl;
push @pl, Player->new(name => Alice, strategy => aggressive);
push @pl, Player->new(name => Bob, strategy => conservative);
my $hand = Hand->new( players, \@pl );
$hand->play();


##</code><code>##

sub new {
    my ($class, %arg) = @_;
# ...
    bless {
# ...
        _players => $arg{players} ,
    }, $class;
}

sub play {
    my ($self) = @_;
    my %player;
    $self->{_players}[0]->out();  # this works
    # out() is a member function that prints some info about the Player

    # add key containg ref to 1st player to %player and
    # with value of a reference to a new anonymous hash
    $player{$self->{_players}[0]} = {};
    foreach my $this_player (keys %player) {
        $this_player->out(); # this doesn't
    }
}


##</code><code>##

Can't locate object method "out" via package "Player=HASH(0x1012ac74)" (perhaps you forgot to load "Player=HASH(0x1012ac74)"?) at Hand.pm line 63.