We  are trying  to track  down  a particularly difficult bug that , intermittently,  prevents   users from completing  an  assignment.

In short, your code  might be  correct ,  but  the assignment  does not trigger as correct.

We  are working on tracking this down, but until we patch this bug, there is   one way to fix the issue. Just reload the page and try the assignment again with the exact same code!   (So  make sure you save your code before reloading)

We are publishing this post because we have been getting emails about it. Rest assured we will fix it, but until then please try a reload.