ios使用copy方法调用块目标，但崩溃了

问：

我使用调用调用块复制，我认为它等于[块复制]，但为什么崩溃了？

@implementation MyService
    + (void)load {
        [MyService startRequest:^(id  _Nonnull responseObject, NSError * _Nonnull error) {
            NSLog(@"%@",self);
        }];
    }
    
    + (void)startRequest:(void (^)(id responseObject,NSError *error))object {
        
            SEL sel = @selector(copy);
            NSMethodSignature* methodSign = [object methodSignatureForSelector:sel];
            NSInvocation* invocation = [NSInvocation invocationWithMethodSignature:methodSign];
            [invocation setSelector:sel];
    
            [invocation setTarget:object];
            [invocation invoke];
    }
@end