I'm not sure your example will completely work as shown. The first shift in your sub will pull off a reference to the array, not the array itself. So the sub should look something like:

sub cog_class {
    my $cog_ids_ref = shift;
    my $name = shift;

    print "NAME $name\n";

    for my $id ( @{$cog_ids_ref} ){
        # BLAH BLAH
    }
}
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