diff --git a/mmdet/core/fp16/decorators.py b/mmdet/core/fp16/decorators.py
index 10ffbf8..e1e9830 100644
--- a/mmdet/core/fp16/decorators.py
+++ b/mmdet/core/fp16/decorators.py
@@ -56,12 +56,9 @@ def new_func(*args, **kwargs):
             # NOTE: default args are not taken into consideration
             if args:
                 arg_names = args_info.args[:len(args)]
-                for i, arg_name in enumerate(arg_names):
-                    if arg_name in args_to_cast:
-                        new_args.append(
-                            cast_tensor_type(args[i], torch.float, torch.half))
-                    else:
-                        new_args.append(args[i])
+                new_args = [cast_tensor_type(args[i], torch.float, torch.half) 
+                            if arg_name in args_to_cast else args[i] 
+                                for (i, arg_name) in enumerate(arg_names)]
             # convert the kwargs that need to be processed
             new_kwargs = {}
             if kwargs: