switched to load api key into OpenAI class instead of setting environment var

app.py

@@ -57,14 +57,11 @@ def loading_pdf():
 def loading_database(open_ai_key):
     if open_ai_key is not None:
         if os.path.exists(PERSIST_DIRECTORY):
-            os.environ['OPENAI_API_KEY'] = open_ai_key
-            print("Loading from persisted dir")
-            embeddings = OpenAIEmbeddings()
+            embeddings = OpenAIEmbeddings(open_ai_key=open_ai_key)
             docs_retriever = Chroma(persist_directory=PERSIST_DIRECTORY, embedding_function=embeddings)
 
             global qa_chain
             qa_chain = ConversationalRetrievalChain.from_llm(ChatOpenAI(model_name="gpt-3.5-turbo", temperature=0.0),  
-                         
                             retriever=docs_retriever.as_retriever(), 
                             memory=memory, 
                             return_source_documents=False