From 62d2edd165e7240be41ffe730283abaeade4c42e Mon Sep 17 00:00:00 2001
From: YanchaoMa <yanchaoma@foxmail.com>
Date: Sun, 4 Jun 2023 07:53:18 +0800
Subject: [PATCH] Update neo4j_graph.py (#5120)

Remove the version dependencies of neo4j-driver.
[neo4j-driver Test code of different
versions.](https://github.com/crazyyanchao/langchain-crash-course/blob/main/tool-5/app.py)
# Your PR Title (What it does)

<!--
Thank you for contributing to LangChain! Your PR will appear in our next
release under the title you set. Please make sure it highlights your
valuable contribution.

Replace this with a description of the change, the issue it fixes (if
applicable), and relevant context. List any dependencies required for
this change.

After you're done, someone will review your PR. They may suggest
improvements. If no one reviews your PR within a few days, feel free to
@-mention the same people again, as notifications can get lost.
-->

<!-- Remove if not applicable -->

Fixes # (issue)

## Before submitting

<!-- If you're adding a new integration, include an integration test and
an example notebook showing its use! -->

## Who can review?

Community members can review the PR once tests pass. Tag
maintainers/contributors who might be interested:

<!-- For a quicker response, figure out the right person to tag with @

        @hwchase17 - project lead

        Tracing / Callbacks
        - @agola11

        Async
        - @agola11

        DataLoaders
        - @eyurtsev

        Models
        - @hwchase17
        - @agola11

        Agents / Tools / Toolkits
        - @vowelparrot

        VectorStores / Retrievers / Memory
        - @dev2049

 -->
---
 langchain/chains/graph_qa/cypher.py |  9 +++++++--
 langchain/graphs/neo4j_graph.py     | 22 +---------------------
 2 files changed, 8 insertions(+), 23 deletions(-)

diff --git a/langchain/chains/graph_qa/cypher.py b/langchain/chains/graph_qa/cypher.py
index 68966cd277d..3ccdcb93fd0 100644
--- a/langchain/chains/graph_qa/cypher.py
+++ b/langchain/chains/graph_qa/cypher.py
@@ -47,11 +47,16 @@ class GraphCypherQAChain(Chain):
         *,
         qa_prompt: BasePromptTemplate = CYPHER_QA_PROMPT,
         cypher_prompt: BasePromptTemplate = CYPHER_GENERATION_PROMPT,
+        qa_chain: LLMChain = None,
+        cypher_generation_chain: LLMChain = None,
         **kwargs: Any,
     ) -> GraphCypherQAChain:
         """Initialize from LLM."""
-        qa_chain = LLMChain(llm=llm, prompt=qa_prompt)
-        cypher_generation_chain = LLMChain(llm=llm, prompt=cypher_prompt)
+        if qa_chain is None:
+            qa_chain = LLMChain(llm=llm, prompt=qa_prompt)
+
+        if cypher_generation_chain is None:
+            cypher_generation_chain = LLMChain(llm=llm, prompt=cypher_prompt)
 
         return cls(
             qa_chain=qa_chain,
diff --git a/langchain/graphs/neo4j_graph.py b/langchain/graphs/neo4j_graph.py
index 4433771a255..a077a0f469d 100644
--- a/langchain/graphs/neo4j_graph.py
+++ b/langchain/graphs/neo4j_graph.py
@@ -43,27 +43,7 @@ class Neo4jGraph:
         self._driver = neo4j.GraphDatabase.driver(url, auth=(username, password))
         self._database = database
         self.schema = ""
-        # Verify connection
-        try:
-            self._driver.verify_connectivity()
-        except neo4j.exceptions.ServiceUnavailable:
-            raise ValueError(
-                "Could not connect to Neo4j database. "
-                "Please ensure that the url is correct"
-            )
-        except neo4j.exceptions.AuthError:
-            raise ValueError(
-                "Could not connect to Neo4j database. "
-                "Please ensure that the username and password are correct"
-            )
-        # Set schema
-        try:
-            self.refresh_schema()
-        except neo4j.exceptions.ClientError:
-            raise ValueError(
-                "Could not use APOC procedures. "
-                "Please install the APOC plugin in Neo4j."
-            )
+        self.refresh_schema()
 
     @property
     def get_schema(self) -> str: