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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_pretty_app_names(self):
 """ Return the list of pretty app names that are available in the database. Returns: set of str. """

        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