10.9. Dumping hashes

use Data::Dumper qw(Dumper);

print Dumper \%grades;

$VAR1 = {
          'Peti Bar' => {
                          'Art' => 99,
                          'Literature' => 88,
                          'Mathematics' => 82
                        },
          'Foo Bar' => {
                         'Literature' => 67,
                         'Mathematics' => 97
                       }
        };