MeshCombineUtility.cs method GetTriangleStrip' of type UnityEngine.Mesh' could be found

1) Assets/Standard Assets/Scripts/MeshCombineUtility.cs(27,74): error CS1061: Type UnityEngine.Mesh' does not contain a definition for GetTriangleStrip' and no extension method GetTriangleStrip' of type UnityEngine.Mesh' could be found (are you missing a using directive or an assembly reference?)

2) Assets/Standard Assets/Scripts/MeshCombineUtility.cs(130,73): error CS1061: Type UnityEngine.Mesh' does not contain a definition for GetTriangleStrip' and no extension method GetTriangleStrip' of type UnityEngine.Mesh' could be found (are you missing a using directive or an assembly reference?)

3) Assets/Standard Assets/Scripts/MeshCombineUtility.cs(177,30): error CS1061: Type UnityEngine.Mesh' does not contain a definition for SetTriangleStrip' and no extension method SetTriangleStrip' of type UnityEngine.Mesh' could be found (are you missing a using directive or an assembly reference?)