use strict;
use warnings;

my %hash;

if (exists $hash{top}{dependent}) {
    print "\$hash{top}{dependent} exists\n";
} else {
    print "\$hash{top}{dependent} does not exist\n";
}

if (exists $hash{top}) {
    print "\$hash{top} exists\n";
} else {
    print "\$hash{top} does not exist\n";
}

##</code><code>##

$hash{top}{dependent} does not exist
$hash{top} exists