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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 keep_scan(cls, result_key, token):
 """ Define a property that is set to the list of lines that contain the given token. Uses the get method of the log file. """

        def _scan(self):
            return self.get(token)

        cls.scan(result_key, _scan)