Customize SharePoint Content Editor Web Part in VS 2012 classic webpart

1. Paste below code in cs file of classic web part(Not visual web Part)

using System;
using System.ComponentModel;
using System.Web;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Utilities;
using Microsoft.SharePoint.WebControls;
using Microsoft.SharePoint.WebPartPages;
namespace POC2012CEWP.MyClassicCEWP
{
    [ToolboxItemAttribute(false)]
    public class MyClassicCEWP : Microsoft.SharePoint.WebPartPages.WebPart
    {
        private string _content;
        private HtmlGenericControl editableRegion = new HtmlGenericControl();
        private HtmlGenericControl emptyPanel = new HtmlGenericControl();
        private bool IsInEditMode
        {
            get
            {
                SPWebPartManager currentWebPartManager = (SPWebPartManager)WebPartManager.GetCurrentWebPartManager(this.Page);
                return (((currentWebPartManager != null) && !base.IsStandalone) && currentWebPartManager.GetDisplayMode().AllowPageDesign);
            }
        }
        protected override void OnInit(EventArgs e)
        {
            base.OnInit(e);
            if (this.IsInEditMode)
            {
                SPRibbon current = SPRibbon.GetCurrent(this.Page);
                if (current != null)
                {
                    current.MakeTabAvailable("Ribbon.EditingTools.CPEditTab");
                    current.MakeTabAvailable("Ribbon.Image.Image");
                    current.MakeTabAvailable("Ribbon.EditingTools.CPInsert");
                    current.MakeTabAvailable("Ribbon.Link.Link");
                    current.MakeTabAvailable("Ribbon.Table.Layout");
                    current.MakeTabAvailable("Ribbon.Table.Design");
                    if (!(this.Page is WikiEditPage))
                    {
                        current.TrimById("Ribbon.EditingTools.CPEditTab.Layout");
                        current.TrimById("Ribbon.EditingTools.CPEditTab.EditAndCheckout");
                    }
                }
            }
        }