老师您好！我在学Asset Bundle时，跟着教程走的，在打包时就会如下报错：

报错1：

Assets/NewBehaviourScript.cs(5,4): error CS0246: The type or namespace name `MenuItem' could not be found. Are you missing an assembly reference?

报错2：

Assets/NewBehaviourScript.cs(13,5): error CS0103: The name `BuildPipeline' does not exist in the current context
报错3：

Error building Player because scripts had compiler errors

代码如下：

using System.IO;
using UnityEditor;

public class CreateAB  {
  [MenuItem("Assets/BuildAB")]
  static void BuildAB()
  {
    string dir = "AssetBundles";
    if (!Directory.Exists(dir))
    {
      Directory.CreateDirectory(dir);
    }
    BuildPipeline.BuildAssetBundles(dir, BuildAssetBundleOptions.None, BuildTarget.StandaloneWindows64);
  }
}

请老师解答。