private void ValidateDocXNumberingPartExists()
{
var numberingUri = new Uri("/word/numbering.xml", UriKind.Relative);
// If the internal document contains no /word/numbering.xml create one.
if (!Document._package.PartExists(numberingUri))
{
Document._numbering = HelperFunctions.AddDefaultNumberingXml(Document._package);
}
}