Add function to create a new extension element

extensionElement.go

@@ -10,6 +10,10 @@ type ExtensionElement struct {
 	XMLName xml.Name
 }
 
+func NewExtensionElement(name string, value any) *ExtensionElement {
+	return &ExtensionElement{XMLName: xml.Name{Local: name}, Value: value}
+}
+
 func (e *ExtensionElement) Check() error {
 	if e.Value == nil {
 		return errors.New("value element of extension element empty")