SenseNet.ContentRepository.ContentList.GetValidDocument C# (CSharp) Method

        private IXPathNavigable GetValidDocument(string xml)
        {
            if (string.IsNullOrEmpty(xml))
                xml = DefaultContentListDefinition;

            if (RepositoryConfiguration.BackwardCompatibilityXmlNamespaces)
                xml = xml.Replace(ContentListDefinitionXmlNamespaceOld, ContentListDefinitionXmlNamespace);

            var doc = new XPathDocument(new StringReader(xml));
            CheckValidation(doc);
            return doc;
        }
        private static void CheckValidation(IXPathNavigable xml)