diff --git a/lofar-cwl/steps/utils.js b/lofar-cwl/steps/utils.js
index d58c1eecd13aab1d1990a4f84ed92c805e6d690a..711c00ab03dfc1af230f3e891dde819da5775431 100644
--- a/lofar-cwl/steps/utils.js
+++ b/lofar-cwl/steps/utils.js
@@ -22,3 +22,9 @@ function get_losoto_config(step_name) {
     }
     return par
 }
+
+function concatenate_path(object_list){
+    object_list.forEach(function (x, index, arr) {arr[index] = x.path;});
+    return '[' + object_list.join(',') + ']'
+    
+}
\ No newline at end of file