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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 clear(self):
 """ This is a convenience method to clear a batch statement for reuse. *Note:* it should not be used concurrently with uncompleted execution futures executing the same ``BatchStatement``. """

        del self._statements_and_parameters[:]
        self.keyspace = None
        self.routing_key = None
        if self.custom_payload:
            self.custom_payload.clear()