currency api model

Api.swift

enum Api {
    static func getCurrencyExchangeRate(baseCurrency: String = "EUR", firebaseSaveBlock: ((Data) -> Void)? = nil) -> Single<[CurrencyExchangeRate]> {
        return Service.shared.container
            .resolve(MoyaProvider<CurrencyExchangeRateRemoteApi>.self)!.singleRequest(.exchangeRate(baseCurrency: baseCurrency))
            .observeOn(Service.shared.container.resolve(SerialDispatchQueueScheduler.self, name: Service.RegisterationName.cacheSave.rawValue)!)
            .do(onSuccess: { firebaseSaveBlock?($0) })
            .map({ data -> [CurrencyExchangeRate] in
                let exchangeRate = try JSONDecoder().decode(ExchangeRate.self, from: data)
                return exchangeRate.convertCurrencyExchangeRate()
            }).do(onSuccess: { rates in
                CurrencyExchangeRateLocalApi.saveExchangeRate(rates: rates)
            }).observeOn(MainScheduler.instance)
    }
}