/// <summary>
        /// Entry point for the commandlet
        /// </summary>
        public override void ExecuteBuild()
        {
            string ParentDir = ParseParamValue("ParentDir", null);

            if (ParentDir == null)
            {
                throw new AutomationException("Missing -ParentDir parameter");
            }
            ParentDir = Path.GetFullPath(ParentDir);

            string SearchPattern = ParseParamValue("SearchPattern", null);

            if (SearchPattern == null)
            {
                throw new AutomationException("Missing -SearchPattern parameter");
            }

            string Days = ParseParamValue("Days", null);

            if (Days == null)
            {
                CommandUtils.CleanFormalBuilds(ParentDir, SearchPattern);
            }
            else
            {
                int DaysValue;
                if (!int.TryParse(Days, out DaysValue))
                {
                    throw new AutomationException("'{0}' is not a valid value for the -Days parameter", Days);
                }
                CommandUtils.CleanFormalBuilds(ParentDir, SearchPattern, DaysValue);
            }
        }