Crash while requesting SKProducts

Code Block 
Crashed: com.apple.root.default-qos
0  libswiftCore.dylib             0x1a6249d8c swift_isUniquelyReferenced_nonNull_native + 34
1  MyApp                          0x104a2bf7c @objc IAPHandler.productsRequest(_:didReceive:) + 4301487996 (<compiler-generated>:4301487996)
2  StoreKit                       0x1bf3fd6dc __27-[SKProductsRequest _start]_block_invoke_2 + 184
3  libdispatch.dylib              0x1a2149298 _dispatch_call_block_and_release + 24
4  libdispatch.dylib              0x1a214a280 _dispatch_client_callout + 16
5  libdispatch.dylib              0x1a21228bc _dispatch_queue_override_invoke + 676
6  libdispatch.dylib              0x1a212f450 _dispatch_root_queue_drain + 344
7  libdispatch.dylib              0x1a212fbf0 _dispatch_worker_thread2 + 112
8  libsystem_pthread.dylib        0x1ead35568 _pthread_wqthread + 212
9  libsystem_pthread.dylib        0x1ead38874 start_wqthread + 8

Code Block 
func productsRequest (_ request: SKProductsRequest, didReceive response: SKProductsResponse) {
        guard response.products.count > 0 else {
            return
        }
        let iapProducts = response.products
        var iapProductsDict = [String : SKProduct]()
        for product in iapProducts {
            iapProductsDict[product.productIdentifier] = product
        }
}