[Wrapper] add transform repeated and single variants

src/finn/core/modelwrapper.py

@@ -33,6 +33,23 @@ class ModelWrapper:
     def graph(self, value):
         self._model_proto.graph = value
 
+    def transform_repeated(self, transform):
+        """Applies given transform repeatedly until no more changes can be made
+        and returns a transformed ModelWrapper instance.
+        Transform must return (transformed_model, model_was_changed)."""
+        transformed_model = self
+        model_was_changed = True
+        while model_was_changed:
+            (transformed_model, model_was_changed) = transform(transformed_model)
+        return transformed_model
+
+    def transform_single(self, transform):
+        """Applies given transform once and returns transformed ModelWrapper
+        instance. Transform must return (transformed_model, model_was_changed),
+        although model_was_changed is ignored (see also apply_repeated)."""
+        (transformed_model, model_was_changed) = transform(self)
+        return transformed_model
+
     def check_compatibility(self):
         """Checks this model for FINN compatibility:
         * no embedded subgraphs