cr

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)
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langchain/chains/graph_qa/cypher.py

@@ -47,15 +47,20 @@ class GraphCypherQAChain(Chain):
         *,
         qa_prompt: BasePromptTemplate = CYPHER_QA_PROMPT,
         cypher_prompt: BasePromptTemplate = CYPHER_GENERATION_PROMPT,
+        qa_chain: Optional[LLMChain] = None,
+        cypher_generation_chain: Optional[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)
+        _qa_chain = qa_chain or LLMChain(llm=llm, prompt=qa_prompt)
+
+        _cypher_generation_chain = cypher_generation_chain or LLMChain(
+            llm=llm, prompt=cypher_prompt
+        )
 
         return cls(
-            qa_chain=qa_chain,
-            cypher_generation_chain=cypher_generation_chain,
+            qa_chain=_qa_chain,
+            cypher_generation_chain=_cypher_generation_chain,
             **kwargs,
         )
 

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: