I am on the third chapter of the book, trying to implement the canSee and eat methods in greenfoot/java, they don't let my code run for some reason probably because they're inherited methods from the Animal class, and my current Crab class signature extends only the actor class. But i double click the actor class and it gives me an error message stating in a small window "missing or unreadable API documentation". i don't know if it's normal, I stand confused.