The cAlgo builder is always error

using System;
using cAlgo.API;
using cAlgo.API.Internals;
using cAlgo.API.Indicators;
using cAlgo.Indicators;
//using Me.Core.Ind;
//using System.Collections.Generic;

namespace cAlgo
{
    [Indicator(IsOverlay = false, TimeZone = TimeZones.UTC, AccessRights = AccessRights.None)]
    public class Lk : Indicator
    {
        [Parameter(DefaultValue = 0.0)]
        public double Parameter { get; set; }
        //public List<BarInfo> bars;
        [Output("Main")]
        public IndicatorDataSeries Result { get; set; }
        //   public Czsc Czsc;

        protected override void Initialize()
        {
            // Czsc = new Czsc(MarketSeries);
            // Initialize and create nested indicators
        }

        public override void Calculate(int index)
        {
            Result[index] = MarketSeries.Close[index];
        }
    }
}