Fix issues in runnable docs examples (#11883)

docs/docs/expression_language/cookbook/memory.ipynb

@@ -20,7 +20,7 @@
     "from operator import itemgetter\n",
     "from langchain.chat_models import ChatOpenAI\n",
     "from langchain.memory import ConversationBufferMemory\n",
-    "from langchain.schema.runnable import RunnablePassthrough\n",
+    "from langchain.schema.runnable import RunnablePassthrough, RunnableLambda\n",
     "from langchain.prompts import ChatPromptTemplate, MessagesPlaceholder\n",
     "\n",
     "model = ChatOpenAI()\n",
@@ -70,7 +70,7 @@
    "outputs": [],
    "source": [
     "chain = RunnablePassthrough.assign(\n",
-    "    memory=memory.load_memory_variables | itemgetter(\"history\")\n",
+    "    memory=RunnableLambda(memory.load_memory_variables) | itemgetter(\"history\")\n",
     ") | prompt | model\n"
    ]
   },

docs/docs/expression_language/cookbook/retrieval.ipynb

@@ -42,7 +42,7 @@
     "from langchain.chat_models import ChatOpenAI\n",
     "from langchain.embeddings import OpenAIEmbeddings\n",
     "from langchain.schema.output_parser import StrOutputParser\n",
-    "from langchain.schema.runnable import RunnablePassthrough\n",
+    "from langchain.schema.runnable import RunnablePassthrough, RunnableLambda\n",
     "from langchain.vectorstores import FAISS\n"
    ]
   },
@@ -338,7 +338,7 @@
     "# First we add a step to load memory\n",
     "# This adds a \"memory\" key to the input object\n",
     "loaded_memory = RunnablePassthrough.assign(\n",
-    "    chat_history=memory.load_memory_variables | itemgetter(\"history\"),\n",
+    "    chat_history=RunnableLambda(memory.load_memory_variables) | itemgetter(\"history\"),\n",
     ")\n",
     "# Now we calculate the standalone question\n",
     "standalone_question = {\n",
@@ -363,7 +363,7 @@
     "    \"docs\": itemgetter(\"docs\"),\n",
     "}\n",
     "# And now we put it all together!\n",
-    "final_chain = loaded_memory | expanded_memory | standalone_question | retrieved_documents | answer\n"
+    "final_chain = loaded_memory | standalone_question | retrieved_documents | answer\n"
    ]
   },
   {