Objective-C block to Swift Closure translating Estimote "Examples" app -

i'm translating estimote "examples" ios app objective-c swift , have run problem translating following:

@property (nonatomic, copy)     void (^completion)(clbeacon *);  - (id)initwithscantype:(estscantype)scantype completion:(void (^)(id))completion {     self = [super init];     if (self)     {         self.scantype = scantype;         self.completion = [completion copy];     }     return self; }  demoviewcontroller = [[estbeacontablevc alloc] initwithscantype:estscantypebeacon                                                  completion:^(clbeacon *beacon) {    estdistancedemovc *distancedemovc = [[estdistancedemovc alloc] initwithbeacon:beacon];   [self.navigationcontroller pushviewcontroller:distancedemovc animated:yes]; }]; 

how can translated swift? i've tried many solutions other posts , documentation, still haven't gotten right syntax.

first, initializers called init; not have func. , call superclass initializer, super.init(), without needing check return nil. also, class's own properties should initialized before calling superclass initializer:

init(scantype: estscantype completion: (clbeacon? -> void)?) {     self.scantype = scantype     self.completion = completion     super.init() } 

then, create object , call initializer calling name of class. can use trailing closure expression if last argument of call function type. , should use optional chaining instead of forcing optional, preserve same behavior objective-c doesn't crash when called on nil.

demoviewcontroller = estbeacontablevc(scantype:estscantypebeacon) { beacon in   let distancedemovc = estdistancedemovc(beacon:beacon)   self.navigationcontroller?.pushviewcontroller(distancedemovc animated:true) }