Call super of configure(), so required Python package is checked.

Author: sverhoeven

src/main/resources/archetype-resources/plugin/src/java/__node__Model.java

@@ -60,6 +60,6 @@ protected DataTableSpec[] configure(final DataTableSpec[] inSpecs)
         // the spec of its output data table(s) (if you can, otherwise an array
         // with null elements), or throw an exception with a useful user message
 
-        return new DataTableSpec[]{null};
+        return super.configure(inSpecs);
     }
 }