update the code with a custom_loead_learner

app.py

@@ -1,8 +1,24 @@
 from fastai.vision.all import *
 import gradio as gr
+import pathlib
+import fastai.learner
+
+def custom_load_learner(fname, cpu=True, pickle_module=pickle):
+    """Load a Learner from file in `fname` and ensure it's using a platform-independent path."""
+    map_loc = None if torch.cuda.is_available() and not cpu else 'cpu'
+    try:
+        res = torch.load(fname, map_location=map_loc, pickle_module=pickle_module)
+    except ModuleNotFoundError as e:
+        raise ImportError(f"{e}. To load the model on a different device, you may need to install the fastai library.")
+    
+    if 'WindowsPath' in str(type(res.path)):
+        res.path = pathlib.Path(res.path)
+        
+    return res
+
 def is_cat(x): return x[0].isupper()
 
-learn = load_learner('model.pkl')
+learn = custom_load_learner('model.pkl')
 
 categories = ('dog', 'cat')