private Dictionary <ulong, ulong> FillPreviousTradesPairs(ApplicationData thisMonth, ApplicationData prevMonth)
        {
            Dictionary <ulong, ulong> prevMonthList = new Dictionary <ulong, ulong>();

            foreach (UserData user in prevMonth.GetStorage())
            {
                UserData nextUser;
                if (thisMonth.Get(user.UserId) != null && prevMonth.Next(user.UserId, out nextUser))
                {
                    prevMonthList.Add(user.UserId, nextUser.UserId);
                }
            }
            return(prevMonthList);
        }