model.base: make extending a ConstrainedList atomic

Previously partial additions of elements via a call to `.extend()` were
possible, since the `.extend()` method of the superclass simply calls
`.append()` for each item, which in turn calls `.insert()`. Thus, if the
hook call for one item raised an exception, all previous items had
already been added.

basyx/aas/model/base.py

@@ -1223,6 +1223,16 @@ def insert(self, index: int, value: _T) -> None:
             self._item_add_hook(value, self._list)
         self._list.insert(index, value)
 
+    def extend(self, values: Iterable[_T]) -> None:
+        v_list = list(values)
+        if self._item_add_hook is not None:
+            to_add: List[_T] = []
+            for v in v_list:
+                self._item_add_hook(v, self._list + to_add)
+                to_add.append(v)
+        for v in v_list:
+            self._list.append(v)
+
     @overload
     def __getitem__(self, index: int) -> _T: ...