presto-main/src/main/java/io/prestosql/execution/scheduler/NodeSchedulerConfig.java/NodeSchedulerConfig/toNodeSchedulerPolicy
class NodeSchedulerConfig:    private static NodeSchedulerPolicy toNodeSchedulerPolicy(String nodeSchedulerPolicy)
    {
        // "legacy" and "flat" are here for backward compatibility
        switch (nodeSchedulerPolicy.toLowerCase(ENGLISH)) {
            case "legacy":
            case "uniform":
                return NodeSchedulerPolicy.UNIFORM;
            case "flat":
            case "topology":
                return NodeSchedulerPolicy.TOPOLOGY;
            default:
                throw new IllegalArgumentException("Unknown node scheduler policy: " + nodeSchedulerPolicy);
        }
    }