Update agent_langchain.py

agent_langchain.py

@@ -5,6 +5,7 @@ os.environ["HF_HOME"] = "/tmp/huggingface"
 os.environ["SENTENCE_TRANSFORMERS_HOME"] = "/tmp/sentence_transformers"
 os.environ["TORCH_HOME"] = "/tmp/torch"
 
+import json
 import requests
 import torch
 import time