text: **Exercise 7: Use the Create class hierarchy tool to create subclasses of PizzaBase**
  
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  1. Select the class PizzaBase in the class hierarchy. 
  
  2. With PizzaBase selected use the Tools>Create class hierarchy menu option. 
  
  3. This should bring up a wizard that enables you to create a nested group of classes all at once. You 
  should see a window labeled Enter hierarchy where you can enter one name on each line. You can also 
  use the tab key to indicate that a class is a subclass of the class above it. For now we just want to enter 
  two subclasses of PizzaBase: ThinAndCrispyBase and DeepPanBase. One of the things the wizard 
  does is to automatically add a prefix or suffix for us. So just enter ThinAndCrispy, hit return and enter 
  DeepPan. Then in the Suffix field add Base. Your window should look like figure 4.7. 
  
  4. Select Continue. This will take you to a window that asks if you want to make sibling classes disjoint. 
  The default should be checked (make them disjoint) which is what we want in this case (a base can’t be 
  both deep pan and thin) so just select Finish. Synchronize the reasoner. Your class hierarchy should now 
  look like figure 4.8. 