private static async Task <IDictionary <string, decimal> > GetSymbolPriceAsync(IEnumerable <string> symbols, AlphaVantageClient client)
{
var dict = new Dictionary <string, decimal>();
foreach (var symbol in symbols)
{
await Task.Delay(1000);
dict.Add(symbol, (await client.GetQuoteDataAsync(symbol))?.Price ?? throw new ArgumentException($"No data for symbol: {symbol}"));
}
return(dict);
}