Returns set of profile names referenced in this Registry

        :return: set of profile name strings

def get_profiles(self):
        """Returns set of profile names referenced in this Registry

        :return: set of profile name strings
        """
        out = set()
        for ft in self.features.values():
            out.update(ft.get_profiles())
        for ext in self.extensions.values():
            out.update(ext.get_profiles())
        return out