diff --git a/R/ISOInstrumentationEventType.R b/R/ISOInstrumentationEventType.R
index 80514621..46e70ff1 100644
--- a/R/ISOInstrumentationEventType.R
+++ b/R/ISOInstrumentationEventType.R
@@ -32,7 +32,7 @@ ISOInstrumentationEventType <- R6Class("ISOInstrumentationEventType",
     #'@param xml object of class \link[XML]{XMLInternalNode-class}
     #'@param value value
     #'@param description description
-    initialize = function(xml = NULL, value, description = NULL){
+    initialize = function(xml = NULL, value = NULL, description = NULL){
       super$initialize(xml = xml, id = private$xmlElement, value = value, description = description, 
                        addCodeSpaceAttr = FALSE)
     }