Solution to Exo2

To optimize the roof, a new action of "WallModification" is added to `design_space_exo2.py :

   X4_act = {
        "Category": "WallModification",

     (...)

        "Description": {
            "TargetSurfaceNames": ["Roof"],
            "Layer2RemoveIndexes": [],
            "LayerInsert": [],
            "TargetConstructionName": "Toit",
        },
    }
    X4 = {
        "Action": X4_act,
        "Variables": ["LayerInsert"],        
        "SearchSpace": {
            "LayerInsert": {"Type": "discrete", "Law": "uniform", "Bounds": {"choices": choices_insulation_layer}},
        },
    }

It was necessary to create a new variable (in addition to X2_act ) because the roof and the walls are not made of the same Construction. In other words, the composite (Construction) the walls and the roof are made of are different. The variable X4 adds a layer to the inside of the construction "Toit", whose original composition is given in cabin.idf

Construction,
    Toit,                    !- Name
    PUR 30mm;                !- Outside Layer
    # and X4 will add a layer here