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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 cancel_spot_instance_requests(self, request_ids):
 """ Cancel the specified Spot Instance Requests. :type request_ids: list :param request_ids: A list of strings of the Request IDs to terminate :rtype: list :return: A list of the instances terminated """

        params = {}
        if request_ids:
            self.build_list_params(params, request_ids, 'SpotInstanceRequestId')
        return self.get_list('CancelSpotInstanceRequests', params,
                             [('item', Instance)], verb='POST')