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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 querystring(self):
 """Return original querystring but containing only managed keys :return dict: dict of managed querystring parameter """

        return {key: value for (key, value) in self.qs.items()
                if key.startswith(self.MANAGED_KEYS) or self._get_key_values('filter[')}