KVO observation done right

Class.m

static void * const kKVOContext = (void *)&kKVOContext;

@implementation Class

- (void)someMethod {
    [super someMethod];
    [observedObject addObserver:self 
                     forKeyPath:@"keyPath"
                        options:NSKeyValueObservingOptionInitial
                        context:kKVOContext];
}

- (void)dealloc
{
    [observedObject removeObserver:self forKeyPath:@"keyPath" context:kKVOContext];
}

- (void)observeValueForKeyPath:(NSString *)keyPath
                      ofObject:(id)object
                        change:(NSDictionary *)change
                       context:(void *)context {
    if (context != kKVOContext) {
        [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
        return;
    }
}