Fix problem reported by lint

aspen/model.py

@@ -97,7 +97,7 @@ def forward(self, data: torch.Tensor) -> torch.Tensor:
 
 class Linear():
     def __init__(self, weight: torch.Tensor, load_in_8bit: bool = True, device: str = None):
-        if device == None:
+        if device is None:
             device = weight.device
         row, col = weight.shape
         if load_in_8bit:

mlora.py

@@ -44,7 +44,7 @@ def log(msg: str):
     exit(-1)
 
 
-if args.model_name_or_path == None:
+if args.model_name_or_path is None:
     print('error: Argument --model_name_or_path are required.')
     parser.print_help()
     exit(-1)