public override string execute(Blackfin bf, string[] args)
            {
                try
                {
                    DateTime startTime = DateTime.Parse(args[0]);
                    DateTime endTime   = DateTime.Parse(args[1]);


                    if (!(bf.GetCounts(startTime, endTime)))
                    {
                        return(null);
                    }
                    return(PrintCountsList(bf.Counts));
                }
                catch (FormatException)
                {
                    throw new IOException("Could not parse start or end dates");
                }
            }