diff --git a/pylasu/model/model.py b/pylasu/model/model.py
index d529775..ce7cb90 100644
--- a/pylasu/model/model.py
+++ b/pylasu/model/model.py
@@ -5,8 +5,7 @@
 
 from .position import Position, Source
 from .reflection import Multiplicity, PropertyDescription
-from ..reflection import getannotations
-from ..reflection.reflection import is_sequence_type, get_type_arguments
+from ..reflection import getannotations, get_type_arguments, is_sequence_type
 
 
 class internal_property(property):
@@ -177,3 +176,17 @@ def _fields(self):
     @internal_property
     def node_type(self):
         return type(self)
+
+
+def concept_of(node):
+    properties = dir(node)
+    if "__concept__" in properties:
+        node_type = node.__concept__
+    elif "node_type" in properties:
+        node_type = node.node_type
+    else:
+        node_type = type(node)
+    if isinstance(node_type, Concept):
+        return node_type
+    else:
+        raise Exception(f"Not a concept: {node_type} of {node}")
diff --git a/pylasu/reflection/__init__.py b/pylasu/reflection/__init__.py
index c0d0ce1..415e17e 100644
--- a/pylasu/reflection/__init__.py
+++ b/pylasu/reflection/__init__.py
@@ -1 +1 @@
-from .reflection import getannotations
+from .reflection import getannotations, get_type_arguments, is_sequence_type
diff --git a/pylasu/transformation/transformation.py b/pylasu/transformation/transformation.py
index fe06fdd..c09991b 100644
--- a/pylasu/transformation/transformation.py
+++ b/pylasu/transformation/transformation.py
@@ -5,6 +5,7 @@
 
 from pylasu.model import Node, Origin
 from pylasu.model.errors import GenericErrorNode
+from pylasu.model.model import concept_of
 from pylasu.model.reflection import PropertyDescription
 from pylasu.transformation.generic_nodes import GenericNode
 from pylasu.validation import Issue, IssueSeverity
@@ -32,7 +33,7 @@ def set(self, node: Node, value):
 class NodeFactory(Generic[Source, Output]):
     constructor: node_factory_constructor_type
     children: Dict[str, "ChildNodeFactory[Source, Any, Any]"] = field(default_factory=dict)
-    finalizer: Callable[[Source], None] = lambda _: None
+    finalizer: Callable[[Source], None] = field(default=lambda _: None)
 
     def with_child(
             self,
@@ -104,7 +105,7 @@ def transform_into_nodes(self, source: Optional[Any], parent: Optional[Node] = N
         if factory:
             nodes = self.make_nodes(factory, source)
             for node in nodes:
-                for pd in type(node).node_properties:
+                for pd in concept_of(node).node_properties:
                     self.process_child(source, node, pd, factory)
                 factory.finalizer(node)
                 node.parent = parent
@@ -134,7 +135,7 @@ def process_child(self, source, node, pd, factory):
             if child_node_factory != NO_CHILD_NODE:
                 self.set_child(child_node_factory, source, node, pd)
         else:
-            # TODO should we support @Mapped?
+            # TODO should we support @Mapped / dot-notation?
             factory.children[child_key] = NO_CHILD_NODE
 
     def as_origin(self, source: Any) -> Optional[Origin]: