templates: Update neo4j templates (#19789)

templates/neo4j-parent/neo4j_parent/chain.py

@@ -1,10 +1,9 @@
-from langchain_community.chat_models import ChatOpenAI
-from langchain_community.embeddings import OpenAIEmbeddings
 from langchain_community.vectorstores import Neo4jVector
 from langchain_core.output_parsers import StrOutputParser
 from langchain_core.prompts import ChatPromptTemplate
 from langchain_core.pydantic_v1 import BaseModel
 from langchain_core.runnables import RunnableParallel, RunnablePassthrough
+from langchain_openai import ChatOpenAI, OpenAIEmbeddings
 
 retrieval_query = """
 MATCH (node)-[:HAS_PARENT]->(parent)
@@ -12,6 +11,11 @@ WITH parent, max(score) AS score // deduplicate parents
 RETURN parent.text AS text, score, {} AS metadata
 """
 
+
+def format_docs(docs):
+    return "\n\n".join(doc.page_content for doc in docs)
+
+
 vectorstore = Neo4jVector.from_existing_index(
     OpenAIEmbeddings(),
     index_name="retrieval",
@@ -31,7 +35,9 @@ prompt = ChatPromptTemplate.from_template(template)
 model = ChatOpenAI()
 
 chain = (
-    RunnableParallel({"context": retriever, "question": RunnablePassthrough()})
+    RunnableParallel(
+        {"context": retriever | format_docs, "question": RunnablePassthrough()}
+    )
     | prompt
     | model
     | StrOutputParser()