SL: Add scenario support.

src/Model/BoundaryCondition/BoundaryCondition.py

@@ -341,7 +341,7 @@ class BoundaryCondition(SQLSubModel):
                 owner_scenario=owner_scenario
             )
             if deleted:
-                f.set_as_deleted()
+                bc.set_as_deleted()
 
             bc.node = None
             if node != -1:
@@ -549,6 +549,12 @@ class BoundaryCondition(SQLSubModel):
 
         self.modified()
 
+    def undelete(self, els):
+        for el in els:
+            el.set_as_not_deleted()
+
+        self.modified()
+
     def sort(self, _reverse=False, key=None):
         if key is None:
             self._data.sort(reverse=_reverse)