code: public BigMoney toBigMoney() {
          if (currency == null) {
              throw new MoneyFormatException("Cannot convert to BigMoney as no currency found");
          }
          if (amount == null) {
              throw new MoneyFormatException("Cannot convert to BigMoney as no amount found");
          }
          return BigMoney.of(currency, amount);
      }
docs: Converts the context to a {@code BigMoney}.
  
  @return the monetary value, never null
  @throws MoneyFormatException if either the currency or amount is missing