text: Note in figure 4.18 the two classes listed under Disjoint With and highlighted in yellow. This is an 
  example of an inference from the reasoner. When we defined Pizza, PizzaBase, and PizzaTopping 
  we made those 3 classes disjoint. I.e., no individual can be a member of more than one of those classes. 
  Since MargheritaPizza is a subclass of Pizza it is also disjoint with PizzaBase and 
  PizzaTopping, so the reasoner has added this information to the definition of MargheritaPizza and 
  as with all inferences from the reasoner highlighted the new information in yellow. 
  
  We will now create the class to represent an AmericanaPizza, which has toppings of pepperoni, 
  mozzarella and tomato. Because the class AmericanaPizza is similar to the class MargheritaPizza 
  (i.e., an AmericanaPizza is almost the same as a MargheritaPizza but with an extra topping of 
  pepperoni) we will make a clone of the MargheritaPizza class and then add an extra restriction to say 
  that it has a topping of pepperoni. 
  
  **Exercise 16: Create AmericanaPizza by Cloning MargheritaPizza and Adding Additional**
  **Restrictions**
  
  __ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ___