Update app.py to drop preamble

app.py

@@ -1,21 +1,15 @@
+from llama_index.llms.openai import OpenAI
+from llama_index.core.schema import MetadataMode
 import os
+import openai
 os.environ["OPENAI_API_KEY"]
+import logging
+import sys
+llm = OpenAI(temperature=0.0, model="gpt-3.5-turbo", max_tokens=512)
 
-from llama_index import (
-    VectorStoreIndex,
-    SummaryIndex,
-    SimpleKeywordTableIndex,
-    SimpleDirectoryReader,
-    ServiceContext,
-    StorageContext,
-    load_index_from_storage
-)
-from llama_index.schema import IndexNode
-from llama_index.tools import QueryEngineTool, ToolMetadata
-from llama_index.llms import OpenAI
+import nest_asyncio
 
-llm = OpenAI(temperature=0, model="gpt-3.5-turbo")
-service_context = ServiceContext.from_defaults(llm=llm)
+nest_asyncio.apply() 
 
 PERSIST_DIR = "arv_metadata"
 storage_context = StorageContext.from_defaults(persist_dir=PERSIST_DIR)
@@ -57,7 +51,7 @@ def nishauri(question: str, conversation_history: list[str]):
     
     
     context = " ".join([item["user"] + " " + item["chatbot"] for item in conversation_history])
-    response = query_engine.query(preamble +
+    response = query_engine.query(#preamble +
                                   "the user previously asked and received the following: " +
                                   context +
                                   prompt_intro +