diff --git a/flax/__init__.py b/flax/__init__.py
index 1341b3065..680456976 100644
--- a/flax/__init__.py
+++ b/flax/__init__.py
@@ -37,3 +37,4 @@
 from . import linen
 from . import nn
 from . import optim
+# DO NOT REMOVE - Marker for internal logging.
diff --git a/flax/nn/base.py b/flax/nn/base.py
index 7b6f83862..5b3a3e619 100644
--- a/flax/nn/base.py
+++ b/flax/nn/base.py
@@ -38,7 +38,6 @@
 from jax import random
 
 
-
 _module_stack = utils.CallStack()
 _module_output_trackers = utils.CallStack()
 _state_stack = utils.CallStack()
@@ -272,6 +271,7 @@ class Module(metaclass=_ModuleMeta):
 
   def __new__(cls, *args, name=None, **kwargs):
     warnings.warn("The `flax.nn` module is Deprecated, use `flax.linen` instead. Learn more and find an upgrade guide at https://github.com/google/flax/blob/master/flax/linen/README.md", DeprecationWarning)
+    # DO NOT REMOVE - Marker for internal logging.
     if not _module_stack:
       raise ValueError('A Module should only be instantiated directly inside'
                        ' another module.')