如何从Perl中的现有哈希创建匿名哈希？

#!/usr/bin/perl
use strict;
use warnings;

my %existing_hash = (
    key1 => 'value1',
    key2 => 'value2',
    key3 => 'value3',
);

my $anon_hash = { map { $_ => $existing_hash{$_} } keys %existing_hash };

print "Anonymous hash: ", join(", ", map { "$_ => $anon_hash->{$_}" } keys %$anon_hash), "\n";