Update app.py

app.py

@@ -48,13 +48,13 @@ retriever = PineconeHybridSearchRetriever(
 )
 
 
-LANGCHAIN_TRACING_V2 = os.environ('LANGCHAIN_TRACING_V2')
+LANGCHAIN_TRACING_V2 = os.getenv('LANGCHAIN_TRACING_V2')
 
-LANGCHAIN_ENDPOINT = os.environ('LANGCHAIN_ENDPOINT')
+LANGCHAIN_ENDPOINT = os.getenv('LANGCHAIN_ENDPOINT')
 
-LANGCHAIN_PROJECT = os.environ('LANGCHAIN_PROJECT')
+LANGCHAIN_PROJECT = os.getenv('LANGCHAIN_PROJECT')
 
-LANGCHAIN_API_KEY = os.environ('LANGCHAIN_API_KEY')
+LANGCHAIN_API_KEY = os.getenv('LANGCHAIN_API_KEY')
 
 
 # ========== PART 4 ==========