XML C#

using System;
using System.Linq;
using System.Xml;
using System.Xml.Linq;
using System.Collections;
using System.Collections.Generic;
using System.Xml.XPath;
public class MainClass{
   public static void Main(){
            
      XmlDocument document = new XmlDocument();
      document.Load("domainBooks.xml");
      XPathNavigator navigator = document.CreateNavigator();
      
      XmlNamespaceManager manager = new XmlNamespaceManager(document.NameTable);
      manager.AddNamespace("bk", "http://www.domain.com/books");
      
      XPathNavigator first = navigator.SelectSingleNode("/bk:bookstore/bk:book[1]", manager);
      XPathNavigator last = navigator.SelectSingleNode("/bk:bookstore/bk:book[2]", manager);
      
      navigator.MoveTo(first);
      XmlWriter newRange = navigator.ReplaceRange(last);
      newRange.WriteStartElement("book");
      newRange.WriteAttributeString("genre", "Computer");
      newRange.WriteAttributeString("publicationdate", "2005-04-07");
      newRange.WriteAttributeString("ISBN", "0");
      newRange.WriteStartElement("title");
      newRange.WriteString("New Book");
      newRange.WriteEndElement();
      newRange.WriteStartElement("author");
      newRange.WriteStartElement("first-name");
      newRange.WriteString("First Name");
      newRange.WriteEndElement();
      newRange.WriteStartElement("last-name");
      newRange.WriteString("Last Name");
      newRange.WriteEndElement();
      newRange.WriteEndElement();
      newRange.WriteElementString("price", "$0.00");
      newRange.WriteEndElement();
      newRange.Close();
      Console.WriteLine(navigator.OuterXml);
   }
}