Update app.py

app.py

@@ -19,7 +19,7 @@ class LinearModel(torch.nn.Module):
 
 def process(n: int):
     print(f'\n===process step {n}')
-    print('cuda visible devices: ' + os.getenv('CUDA_VISIBLE_DEVICES'))
+    print('cuda visible devices: ' + str(os.getenv('CUDA_VISIBLE_DEVICES')))
     print('cuda avaliable: ' + str(torch.cuda.is_available()))
     print('cuda device count: ' + str(torch.cuda.device_count()))