Update app.py

app.py

@@ -139,6 +139,7 @@ def create_vector_db(final_items):
     global db
     client = chromadb.Client()
     collection_name = "BioModelsRAG"
+    from chromadb.utils import embedding_functions
     embedding_function = embedding_functions.SentenceTransformerEmbeddingFunction(model_name="all-MiniLM-L6-v2")
     
     db = client.get_or_create_collection(name=collection_name, embedding_function = embedding_function)