objective-c - 如何在 Xcode 中读取带有地址的键的值

Question

我的应用程序崩溃并给出输出 value for key devices of object 0xde8a470 is nil，“设备”（NSMutableArray）设置如下：

- (void) centralManager:(CBCentralManager *)central 
didDiscoverPeripheral:(CBPeripheral *)peripheral 
  advertisementData:(NSDictionary *)advertisementData 
               RSSI:(NSNumber *)RSSI 
{
 NSMutableArray *peripherals = [self mutableArrayValueForKey:@"devices"];
    if( ![self.devices containsObject:peripheral] )
        [peripherals addObject:peripheral];  
...
}

我如何知道哪个对象0xde8a470是什么以及如何读取它的值？