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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 url_id(cls):
 """The URL id"""

        if cls.__uuid_primary_key__:
            def url_id_func(self):
                """The URL id, UUID primary key rendered as a hex string"""
                return self.id.hex

            def url_id_is(cls):
                return SqlHexUuidComparator(cls.id)

            url_id_func.__name__ = 'url_id'
            url_id_property = hybrid_property(url_id_func)
            url_id_property = url_id_property.comparator(url_id_is)
            return url_id_property
        else:
            def url_id_func(self):
                """The URL id, integer primary key rendered as a string"""
                return six.text_type(self.id)

            def url_id_expression(cls):
                """The URL id, integer primary key"""
                return cls.id

            url_id_func.__name__ = 'url_id'
            url_id_property = hybrid_property(url_id_func)
            url_id_property = url_id_property.expression(url_id_expression)
            return url_id_property