def METHOD_NAME(self, request, _):
    """Purge desired inventory data.
    Args:
        request (object): gRPC request object.
        _ (object): Unused
    Returns:
        object: gRPC reply object.
    """
    result = self.inventory.purge(request.retention_days)
    return inventory_pb2.PurgeReply(
        result=result)