fix

app/rag.py

@@ -25,6 +25,7 @@ class ChatPDF:
     text_chunks = []
     doc_ids = []
     nodes = []
+    hyde_query_engine = None
 
     def __init__(self):
         logging.basicConfig(level=logging.INFO)
@@ -99,4 +100,5 @@ class ChatPDF:
     def clear(self):
         self.text_chunks = []
         self.doc_ids = []
-        self.nodes = []
+        self.nodes = []
+        self.hyde_query_engine = None