public async Task GetCurrencies()
{
// Account currencies
List <TTCurrency> currencies;
if (string.IsNullOrEmpty(CurrenciesFilter))
{
currencies = await _client.GetAllCurrenciesAsync();
}
else
{
currencies = await _client.GetCurrencyAsync(CurrenciesFilter);
}
Currencies = currencies != null ? new ObservableCollection <TTCurrency>(currencies) : null;
}