查看未知block类型的参数，主要用于越狱开发

• (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { // Override point for customization after application launch.

  [self test:^(UIImage *a){}];

  return YES; }

-(void)test:(id)arg {

NSLog(@"signature %s", BlockSig(arg));

}