ios - Trying to get steps using HealthKit but it's always returning 0.0 -

i'm trying steps half hour ago , i'm using method discussed here. following code:

func getsteps(completion: @escaping (double) -> void) {     let stepsquantitytype = hkquantitytype.quantitytype(foridentifier: .stepcount)!      let = date()     let calendar = calendar.current     let halfhouragodate = calendar.date(byadding: .minute, value: -30, to: now)      if let date = halfhouragodate {         let predicate = hkquery.predicateforsamples(withstart: date, end: now, options: .strictstartdate)          let query = hkstatisticsquery(quantitytype: stepsquantitytype, quantitysamplepredicate: predicate, options: .cumulativesum) { (_, result, error) in             var resultcount = 0.0              guard let result = result else {                 completion(resultcount)                 return             }              if let sum = result.sumquantity() {                 resultcount = sum.doublevalue(for: hkunit.count())                 return             }              dispatchqueue.main.async {                 completion(resultcount)             }         }          healthstore.execute(query)      } else {         print("error mainvc, date being cast nil")     } } 

when try steps, code:

 var todayssteps: double = 0  getsteps(completion: { (resultcount) -> void in                                 todayssteps = resultcount                             })  print(todayssteps) // comes out 0.0 

yet whenever run code, code returns 0.0. i've enabled healthkit, , authorized steps, i'm not sure reason is. note in variable declarations:

let healthstore = hkhealthstore()