add short dict and getter in HS

src/Model/HydraulicStructures/Basic/Types.py

@@ -35,3 +35,8 @@ class NotDefined(BasicHS):
             BHSValue("bar", float, 42.0),
             BHSValue("baz", int, 13),
         ]
+
+
+BHS_types = {
+    "ND": NotDefined,
+}

src/Model/HydraulicStructures/HydraulicStructures.py

@@ -233,6 +233,9 @@ class HydraulicStructure(SQLSubModel):
     def basic_structures(self):
         return self._data.copy()
 
+    def basic_structure(self, index: int):
+        return self._data[index]
+
     def add(self, index: int):
         value = NotDefined(status=self._status)
         self._data.insert(index, value)