Update app.py

app.py

@@ -199,11 +199,14 @@ def create_collection_name(filepath):
 
 #collection_name, vector_db, btn, llm_btn, slider_temperature, slider_maxtokens, slider_topk]
 def build_qa_chain(collection_name, vector_db, file: str, llm_option, temperature, max_tokens, top_k, progress=gr.Progress()):
-    print("in build_qa_chain="+file.name) 
 
-    if file == None:
+    if file == None or not file:
         raise gr.Error("Please upload a PDF first!")
         
+    print("in build_qa_chain="+file.name) 
+
+    
+        
     documents, file_name = process_file2(file)
     
     # Load embeddings model