System.Xml.Xsl.XsltOld.SortAction.ParseDataType C# (CSharp) Method

        private XmlDataType ParseDataType(string value, InputScopeManager manager) {
            if(value == null) { // Avt is not constant, or attribute wasn't defined
                return XmlDataType.Text; 
            }
            if (value == Keywords.s_Text) {
                return XmlDataType.Text;
            }
            if (value == Keywords.s_Number) {
                return XmlDataType.Number; 
            }
            String prefix, localname;
            PrefixQName.ParseQualifiedName(value, out prefix, out localname);
			manager.ResolveXmlNamespace(prefix);
            if (prefix.Length == 0 && ! this.forwardCompatibility) {
                throw XsltException.Create(Res.Xslt_InvalidAttrValue, Keywords.s_DataType, value); 
            }
            return XmlDataType.Text;
        }