fixing error

app.py

@@ -10,6 +10,7 @@ from langchain.chat_models import ChatOpenAI
 from langchain.memory import ConversationBufferMemory
 from langchain.chains import RetrievalQA, LLMChain
 from langchain.prompts import PromptTemplate
+from langchain.embeddings import OpenAIEmbeddings
 
 
 # embedding_file = "all_faiss_store_openai.pkl"
@@ -148,11 +149,13 @@ def slow_echo(usr_message, chat_history):
         # Handle OpenAI-specific errors
         error_message = f"OpenAI API Error: {e}"
         print(error_message)
+        return error_message, chat_history
 
     except Exception as e:
         # Handle other unexpected errors
         error_message = f"Unexpected error: {e}"
         print(error_message)
+        return error_message, chat_history
 
 
 with gr.Blocks() as demo: