my $it3 = append (upto(1,3), list_iterator qw(foo bar baz), upto (7,9));
print_it $it3;

##</code><code>##

Invalid append 1
$VAR1 = 1;
$VAR1 = 2;
$VAR1 = 3;
$VAR1 = 'foo';
$VAR1 = 'bar';
$VAR1 = 'baz';
$VAR1 = sub {
            use warnings;
            use strict 'refs';
            return $start <= $end ? $start++ : undef;
        };

##</code><code>##

print "\n\nInvalid append 1\n";
my $it3 = append upto(1,3), list_iterator (qw(foo bar baz)), upto (7,9);
print_it $it3;

##</code><code>##

Invalid append 1
$VAR1 = 1;
$VAR1 = 2;
$VAR1 = 3;
$VAR1 = 'foo';
$VAR1 = 'bar';
$VAR1 = 'baz';
$VAR1 = 7;
$VAR1 = 8;
$VAR1 = 9;