ctr1 = test_nested_func();
ctr2 = test_nested_func(10);
keyboard
disp(ctr1.get_count()); % 2
disp(ctr2.get_count()); % 10
ctr1.increase();
ctr2.decrease();
disp(ctr1.get_count()); % 3
disp(ctr2.get_count()); % 9
