use v5.20;
use List::Util qw(any none);

# Allows the first arg to be an array or a ref
# If the second arg is absent, $_ is used instead
sub in:prototype(+_) { any { $_[1] eq $_ } @{ $_[0] } }
sub notin:prototype(+_) { none { $_[1] eq $_ } @{ $_[0] } }

my @list = 'A'..'Z';

my $in = 'C';
say 'IN' if in @list, $in;

$_ = '1';
say 'OUT' if notin \@list;

say 'NOPE' if in @list, '2';
say 'NOPE' if notin @list, 'D';