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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 freeze(self):
 """Freeze self."""


        if self.no_match:
            return ct.SelectorNull()
        else:
            return ct.Selector(
                self.tag,
                tuple(self.ids),
                tuple(self.classes),
                tuple(self.attributes),
                tuple(self.nth),
                tuple(self.selectors),
                self._freeze_relations(self.relations),
                self.rel_type,
                tuple(self.contains),
                tuple(self.lang),
                self.flags
            )