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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 make_id(self):
 """Create a new URL id that is unique to the parent container"""

        if self.url_id is None:  # Set id only if empty
            self.url_id = select([func.coalesce(func.max(self.__class__.url_id + 1), 1)],
                self.__class__.parent == self.parent)