Another possibility would be the Scope::Upper module:

use Scope::Upper 'reap';

foo(4);
foo(6);

sub foo
{
    my ($n) = @_;

    reap { print "\$n = >$n<\n" };  # <-- Exec block when sub exits

    return 1 if $n < 5;
    $n *= 52;
    return $n;
}
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