C# add new text strings after the searched text string in word document

using Spire.Doc;
using Spire.Doc.Documents;
using Spire.Doc.Fields;
using System.Drawing;

namespace Word
{
    class Program
    {
        static void Main(string[] args)
        {
            //load the sample document
            Document doc = new Document();
            doc.LoadFromFile("Sample.docx", FileFormat.Docx2010);

            //find all the text string “New Zealand” from the sample document
            TextSelection[] selections = doc.FindAllString("New Zealand", true, true);
            int index = 0;

            //defines text range
            TextRange range = new TextRange(doc);


            //insert new text string (NY) after the searched text string
            foreach (TextSelection selection in selections)
            {
                range = selection.GetAsOneRange();
                TextRange newrange = new TextRange(doc);
                newrange.Text = ("(NY)");
                index = range.OwnerParagraph.ChildObjects.IndexOf(range);
                range.OwnerParagraph.ChildObjects.Insert(index + 1, newrange);

            }

            //find and highlight the newly added text string NY
            TextSelection[] text2 = doc.FindAllString("NY", false, true);
            foreach (TextSelection seletion in text2)
            {
                seletion.GetAsOneRange().CharacterFormat.HighlightColor = Color.Yellow;
            }

            //save the document 
            doc.SaveToFile("Result.docx", FileFormat.Docx2010);
        }
    }
}