code: public Map<String, BigDecimal> getCoinbaseExchangeRates() throws IOException {
  
      return coinbase.getCurrencyExchangeRates(Coinbase.CB_VERSION_VALUE).getData().getRates();
    }
docs: Unauthenticated resource that returns BTC to fiat (and vice versus) exchange rates in various
  currencies.
  
  @return Map of lower case directional currency pairs, i.e. btc_to_xxx and xxx_to_btc, to
  exchange rates.
  @throws IOException
  @see <a
  href="https://developers.coinbase.com/api/v2#exchange-rates">developers.coinbase.com/api/v2#exchange-rates</a>