+ use python mode for machine detection

simple.yml

@@ -21,8 +21,8 @@ parameterset:
   - name: benchParam
     parameter:
       - name: input_value
-        _: 43.45
-      
+        mode: python
+        _: '{ "jurecadc" : 1.0 , "jedi" : 2.0 }["${system_name}"]'
 step:
   - name: execute
     use: