Define static NSDictionary, but when second invoke will be crash. For fixing that we must set "onceToken=0" for pre-invoke getStaticInfo before.

static NSDictionary

static NSDictionary *inst = nil;
static dispatch_once_t onceToken = 0;

+(NSDictionary *) getStaticInfo{
    dispatch_once(&onceToken, ^{
        inst = @{
                 @"": @[]
                };
    });
    return inst;
}