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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 assure_relation(cls, cms_page):
 """ Assure that we have a foreign key relation, pointing from CascadePage onto CMSPage. """

        try:
            cms_page.cascadepage
        except cls.DoesNotExist:
            cls.objects.create(extended_object=cms_page)