closures_types_style.swift

//#1 Не указываем
service.searchWithKeyword(keyword,
    offset: offset,
    limit: limit,
    completion: { result in
        //...
    }
    failure: { error in
        //...
    })


//#2 Указываем
service.searchWithKeyword(keyword,
    offset: offset,
    limit: limit,
    completion: { (result: [Transaction]) in
        //...
    }
    failure: { (error: Error) in
        //...
    })