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  Having created the class MargheritaPizza we now need to specify the toppings that it has. To do this we 
  will add two restrictions to say that a MargheritaPizza has the toppings MozzarellaTopping and 
  TomatoTopping. 
  
  **Exercise 15: Create Restrictions that define a MargheritaPizza**
  
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  1. Select MargheritaPizza from the class hierarchy on the Classes tab. 
  
  2. Click on the Add icon (+) next to the SubClass Of field in the Description view for Pizza. 
  
  3. This again brings up the restriction dialogue. This time rather than use the Object restriction creator we 
  will use the Class expression editor tab. Select that tab. 
  
  4. Type hasTopping some Mo into the field. Rather than type the rest of the name of the topping now hit 
  <control><space> (hold down the control key and hit the space bar). Protégé should auto-complete the 
  name for you and the field should now contain: hasTopping some MozzarellaTopping. This is a useful 
  technique for any part of the Protégé UI. Whenever you enter the name of some entity you can do 