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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 prepare(self, engine, mode, items) -> None: """ Create a unique transaction id and dumps the items into a cached request object. """

        self.tx_id = str(uuid.uuid4()).replace("-", "")
        self.engine = engine
        self.mode = mode
        self.items = items
        self._prepare_request()