Better yet, change

my $test = new Hi(
   test_a => 'hello',
   test_b => \sub{ return 1 },
   test_c => \sub{ get_me( $get_a, $get_b ) },
);
[download]

to

my $test = new Hi(
   test_a => 'hello',
   test_b => sub{ return 1 },
   test_c => sub{ get_me( $get_a, $get_b ) },
);
[download]

There's no reason for the extra level of indirect.