diff --git a/docs/extras/modules/chains/how_to/learned_prompt_optimization.ipynb b/docs/extras/modules/chains/how_to/learned_prompt_optimization.ipynb
index 87bb3613c4..9d9a055c9e 100644
--- a/docs/extras/modules/chains/how_to/learned_prompt_optimization.ipynb
+++ b/docs/extras/modules/chains/how_to/learned_prompt_optimization.ipynb
@@ -36,16 +36,6 @@
    "execution_count": 2,
    "metadata": {},
    "outputs": [
-    {
-     "name": "stderr",
-     "output_type": "stream",
-     "text": [
-      "/home/olgavrou/langchain/.testlcvenv/lib/python3.8/site-packages/langchain/utils/utils.py:155: UserWarning: WARNING! engine is not default parameter.\n",
-      "                engine was transferred to model_kwargs.\n",
-      "                Please confirm that engine is what you intended.\n",
-      "  warnings.warn(\n"
-     ]
-    },
     {
      "data": {
       "text/plain": [
@@ -112,16 +102,7 @@
    "cell_type": "code",
    "execution_count": 4,
    "metadata": {},
-   "outputs": [
-    {
-     "name": "stderr",
-     "output_type": "stream",
-     "text": [
-      "/home/olgavrou/langchain/.testlcvenv/lib/python3.8/site-packages/tqdm/auto.py:21: TqdmWarning: IProgress not found. Please update jupyter and ipywidgets. See https://ipywidgets.readthedocs.io/en/stable/user_install.html\n",
-      "  from .autonotebook import tqdm as notebook_tqdm\n"
-     ]
-    }
-   ],
+   "outputs": [],
    "source": [
     "import langchain.chains.rl_chain as rl_chain\n",
     "\n",
diff --git a/libs/langchain/langchain/chains/rl_chain/base.py b/libs/langchain/langchain/chains/rl_chain/base.py
index 4b5ac572f9..26ac9a43e1 100644
--- a/libs/langchain/langchain/chains/rl_chain/base.py
+++ b/libs/langchain/langchain/chains/rl_chain/base.py
@@ -166,7 +166,7 @@ class Event(Generic[TSelected], ABC):
 TEvent = TypeVar("TEvent", bound=Event)
 
 
-class Policy(ABC):
+class Policy(Generic[TEvent], ABC):
     def __init__(self, **kwargs: Any):
         pass