diff --git a/hamilton/graph_utils.py b/hamilton/graph_utils.py
index 8c3695b4..a629f739 100644
--- a/hamilton/graph_utils.py
+++ b/hamilton/graph_utils.py
@@ -3,8 +3,8 @@
 from typing import Callable, List, Tuple
 
 
-def is_submodule(child: ModuleType, parent: ModuleType):
-    return parent.__name__ in child.__name__
+def is_submodule(child: str, parent: str):
+    return parent in child
 
 
 def find_functions(function_module: ModuleType) -> List[Tuple[str, Callable]]:
@@ -18,7 +18,7 @@ def valid_fn(fn):
         return (
             inspect.isfunction(fn)
             and not fn.__name__.startswith("_")
-            and is_submodule(inspect.getmodule(fn), function_module)
+            and is_submodule(fn.__module__, function_module.__name__)
         )
 
     return [f for f in inspect.getmembers(function_module, predicate=valid_fn)]
diff --git a/hamilton/node.py b/hamilton/node.py
index 505c5102..7148b287 100644
--- a/hamilton/node.py
+++ b/hamilton/node.py
@@ -189,7 +189,7 @@ def from_fn(fn: Callable, name: str = None) -> "Node":
         if name is None:
             name = fn.__name__
         sig = inspect.signature(fn)
-        module = inspect.getmodule(fn).__name__
+        module = fn.__module__
         return Node(
             name,
             sig.return_annotation,