Update app.py

app.py

@@ -497,8 +497,8 @@ class Application:
         # Sync parameters with session state
         if all(x in st.session_state for x in ["category", "name", "year"]):
             # Copy session year if category and name are unchanged
-            params["year"] = str(st.session_state["year"]) if all(params[x] == st.session_state[x] for x in ["category", "name"]) else None
-            
+            params["year"] = str(st.session_state["year"]) if all(params.get(x) == st.session_state[x] for x in ["category", "name"]) else None
+
             # Copy category and name from session state
             params["category"] = st.session_state["category"]
             params["name"] = st.session_state["name"]