Make element_list_nice output a set

wrappers/modelverse.py

@@ -925,7 +925,7 @@ def element_list_nice(model_name):
     global registered_metamodels
     _input(["element_list_nice", model_name, registered_metamodels[model_name]])
 
-    return json.loads(_handle_output("Success: ", split=" "))
+    return set(json.loads(_handle_output("Success: ", split=" ")))
 
 def connections_between(model_name, source_element, target_element):
     """Gets a list of all allowed connections between the source and target element in the model."""