如何在swift中从HealthKit中获取血氧饱和度？

let healthStore = HKHealthStore()

func requestHealthKitAuthorization() {
    let typesToRead = Set([HKObjectType.quantityType(forIdentifier: .oxygenSaturation)!])
    
    healthStore.requestAuthorization(toShare: nil, read: typesToRead) { (success, error) in
        if success {
            // 用户已授权
        } else {
            // 授权失败
        }
    }
}

func queryOxygenSaturationData() {
    let oxygenSaturationType = HKObjectType.quantityType(forIdentifier: .oxygenSaturation)!
    let query = HKSampleQuery(sampleType: oxygenSaturationType, predicate: nil, limit: HKObjectQueryNoLimit, sortDescriptors: nil) { (query, results, error) in
        if let results = results as? [HKQuantitySample] {
            for sample in results {
                let oxygenSaturation = sample.quantity.doubleValue(for: HKUnit.percent())
                let date = sample.startDate
                // 处理血氧饱和度数据
            }
        }
    }
    
    healthStore.execute(query)
}

<key>NSHealthShareUsageDescription</key>
<string>需要您的权限来访问血氧饱和度数据</string>
<key>NSHealthUpdateUsageDescription</key>
<string>需要您的权限来更新血氧饱和度数据</string>