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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 set_complete(self, object_id: str):
 """Mark the specified object as completed."""

        if object_id in self.active:
            DB.remove_from_list('{}:active'.format(self.type), object_id)
            DB.append_to_list('{}:completed'.format(self.type), object_id)