/// <summary>
/// Asserts whether a currency is compatible with this exchange rate, that is, is the same as <see cref="From"/>.
/// </summary>
/// <param name="from">The currency to check its compatibility againsts the base currency.</param>
/// <exception cref="DifferentCurrencyException"><paramref name="from"/> is not compatible.</exception>
private void assertCompatibility(CurrencyIsoCode from)
{
if (from != From)
{
throw new DifferentCurrencyException(From.AlphabeticCode(), from.AlphabeticCode());
}
}
