Retrieving the value of a variable outside of the scope of an HKSampleQuery

Question

I'm retrieving sleepAnalysis data from HealthKit and want to store these samples in a global array but once I'm outside the scope of the HKSampleQuery, self.globalVariable goes back to it's initial value of an empty array. How can I retrieve these values outside of the query scope?

if let sleepType = HKObjectType.categoryType(forIdentifier: HKCategoryTypeIdentifier.sleepAnalysis) {
        let sortDescriptor = NSSortDescriptor(key: HKSampleSortIdentifierEndDate, ascending: false)
        let query = HKSampleQuery(sampleType: sleepType, predicate: nil,limit: 90, sortDescriptors: [sortDescriptor]) { (query, tmpResult, error)-> Void in
            if error != nil {
                return
            }
            if let result = tmpResult {
                for item in result {
                    if let sample = item as? HKCategorySample {
                        samples.append(sample)
                    }
                }
            }
       healthStore.execute(query)
       }
}

Outside of the let query scope, samples is nil.