code: def get_pretty_app_names(self):
          
          pretty_app_names = set()
          for app_name in self.get_app_names():
              pretty_app_names.add(self.get_name(app_name))
  
          return pretty_app_names
docs: Return the list of pretty app names that are available in the database.
  
          Returns:
              set of str.