public void AddWarning (ResultItem warning)
		{
			if (!ShouldAdd (warning, _warnings))
				return;

			_warnings.Add (warning);
		}
		bool ShouldAdd (ResultItem resultItem, IList<ResultItem> collection)
		{
			if (!_parameters.UniqueErrors)
				return true;

			return !collection.Contains (resultItem);
		}
		public void AddError (ResultItem error)
		{
			if (!ShouldAdd (error, _errors))
				return;

			_errors.Add (error);
		}