Update app.py

app.py

@@ -836,10 +836,10 @@ def classify(platform, UserInput, Images, Textbox2, Textbox3):
                     print("Error: Image data is not available.")
                     return None
 
-            if UserInput.lower() is not None:
+            if UserInput.lower() is not "":
                 caption = UserInput.lower()
             else:
-                caption = ""
+                caption = None
 
             image = cv.imdecode(np.frombuffer(image_data, np.uint8), cv.IMREAD_COLOR)
             image = cv.resize(image, (224, 224))