public static void RemoveExchange(
     ExchangeToCoinMap compare,
     params CryptoExchangeId[] cryptoExchanges
     )
 {
     foreach (var exchange in cryptoExchanges)
     {
         compare.Remove(exchange);
     }
 }
        public ExchangeToCoinMap GetAll(CryptoExchangeId from)
        {
            if (!Exchanges.ContainsKey(from))
            {
                return(null);
            }

            var result = new ExchangeToCoinMap();

            foreach (var to in Exchanges.Keys)
            {
                if (from == to)
                {
                    continue;
                }

                result[to] = GetPair(from, to);
            }

            return(result);
        }