%ha = $obj -> passhash;
foreach $key (keys (%ha)){
    if ($key eq "problem2"){
        foreach (@ha{$key}){
            print "array : @{$_}\n";
        }
    }
}

##</code><code>##

foreach my $arr_ref (@$ha{'problem2'}) {
  print "subarray: @{$arr_ref} \n";
}

##</code><code>##

my %hash;
@hash{qw/one two three/} = qw/1 2 3/;