diff --git a/libs/langchain/langchain/schema/runnable/base.py b/libs/langchain/langchain/schema/runnable/base.py
index 2d6da33ac24..58c06068d92 100644
--- a/libs/langchain/langchain/schema/runnable/base.py
+++ b/libs/langchain/langchain/schema/runnable/base.py
@@ -116,7 +116,7 @@ class Runnable(Generic[Input, Output], ABC):
 
     For example,
 
-    ..code-block:: python
+    .. code-block:: python
 
         from langchain.schema.runnable import RunnableLambda