How about saving us from ourselves?

my @codes = qw(61 31 21 1 44 16 21 11 7 9 37 39 33 3 2 1 0 32 51 41 10
+);

my %codes;
$codes{$_}++ for @codes;
$codes{$_} > 1 ? die "You can't have two of `$_'" : 1 for @codes;
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:)! ( my testing code)

$>perl -e"@a=qw, 1 23 354 3 3 2 2 3 1134 ,;$a{$_}++ for @a;$a{$_}>1? d
+ie 'hey there STUPID '.$_:1 for @a"

hey there STUPID 3 at -e line 1.
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