fix: type error for setting nul

.idea/workspace.xml

@@ -5,10 +5,8 @@
   </component>
   <component name="ChangeListManager">
     <list default="true" id="48e09a2c-c8fe-48db-8b61-cb395ec0aa52" name="Changes" comment="">
-      <change beforePath="$PROJECT_DIR$/.idea/etf-assistant.iml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/etf-assistant.iml" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/app.py" beforeDir="false" afterPath="$PROJECT_DIR$/app.py" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/requirements.txt" beforeDir="false" afterPath="$PROJECT_DIR$/requirements.txt" afterDir="false" />
     </list>
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />

app.py

@@ -3,9 +3,9 @@ import pinecone
 import openai
 
 from langchain.embeddings.openai import OpenAIEmbeddings
-from langchain.text_splitter import CharacterTextSplitter
+# from langchain.text_splitter import CharacterTextSplitter
+# from langchain.document_loaders import PyPDFLoader
 from langchain.vectorstores import Pinecone
-from langchain.document_loaders import PyPDFLoader
 from langchain.chains import ConversationalRetrievalChain
 from langchain.chat_models import ChatOpenAI
 import streamlit as st
@@ -21,18 +21,23 @@ def _initialize_env():
 
 
 def _initialize_indexes():
-    loader = PyPDFLoader("./etf-book.pdf")
-    documents = loader.load()
-    text_splitter = CharacterTextSplitter(chunk_size=1000, chunk_overlap=0)
-    docs = text_splitter.split_documents(documents)
     embeddings = OpenAIEmbeddings()
 
-    db = Pinecone.from_documents(
-        docs,
-        embeddings,
-        index_name=st.secrets["pinecone_table_name"]
+    # loader = PyPDFLoader("./etf-book.pdf")
+    # documents = loader.load()
+    # text_splitter = CharacterTextSplitter(chunk_size=1000, chunk_overlap=0)
+    # docs = text_splitter.split_documents(documents)
+    # db = Pinecone.from_documents(
+    #     docs,
+    #     embeddings,
+    #     index_name=st.secrets["pinecone_table_name"]
+    # )
+
+    db_object = Pinecone.from_existing_index(
+        st.secrets["pinecone_table_name"],
+        embeddings
     )
-    return db
+    return db_object
 
 
 def _initialize_retriever(db_object):
@@ -50,13 +55,12 @@ chat_history = []
 def answer(user_input):
     if user_input == '':
         return
-    print("----------", user_input)
     global chat_history
     result = qa({
         "question": user_input,
         "chat_history": chat_history
     })
-    chat_history = chat_history.append((user_input, result["answer"]))
+    chat_history.append((user_input, result["answer"]))
     chat_history = chat_history[-10:]
     st.write(
         "Bot: ",