XML VB.Net

Option Explicit
Option Strict
Imports System
Imports System.IO
Imports System.Xml
Public Class Sample
    Private Shared filename As String = "sampledata.xml"
    Public Shared Sub Main()
        Dim writer As XmlTextWriter = Nothing
        writer = New XmlTextWriter(filename, Nothing)
        writer.Formatting = Formatting.Indented
        writer.WriteStartElement("schema")
        writer.WriteAttributeString("xmlns", Nothing, "http://www.w3.org/2001/XMLSchema")
        writer.WriteAttributeString("xmlns", "po", Nothing, "http://domain.com/po")
        writer.WriteStartElement("element")
        writer.WriteAttributeString("name", "purchaseOrder")
        writer.WriteStartAttribute(Nothing, "type", Nothing)
        writer.WriteQualifiedName("data", "http://domain.com/po")
        writer.WriteEndAttribute()
        writer.WriteEndElement()
        writer.WriteEndElement()
        writer.Flush()
        writer.Close()
        Dim doc As New XmlDocument()
        doc.PreserveWhitespace = True
        doc.Load(filename)
        Console.Write(doc.InnerXml)
    End Sub 
End Class