2939 fixes B904 error

monai/_extensions/loader.py

@@ -34,7 +34,7 @@ def timeout(time, message):
     except KeyboardInterrupt as e:
         if timer is not None and timer.is_alive():
             raise e  # interrupt from user?
-        raise TimeoutError(message)
+        raise TimeoutError(message) from e
     finally:
         if timer is not None:
             try:

monai/data/grid_dataset.py

@@ -141,7 +141,7 @@ def __iter__(self):
         try:
             iter_end = len(self.dataset)  # TODO: support iterable self.dataset
         except TypeError:
-            raise NotImplementedError("image dataset must implement `len()`.")
+            raise NotImplementedError("image dataset must implement `len()`.") from None
 
         if worker_info is not None:
             # split workload

monai/data/utils.py

@@ -283,7 +283,7 @@ def list_data_collate(batch: Sequence):
                 + "`DataLoader` with `collate_fn=pad_list_data_collate` might solve this problem (check its "
                 + "documentation)."
             )
-        raise RuntimeError(re_str)
+        raise RuntimeError(re_str) from re
     except TypeError as re:
         re_str = str(re)
         if "numpy" in re_str and "Tensor" in re_str:
@@ -294,7 +294,7 @@ def list_data_collate(batch: Sequence):
                 + "creating your `DataLoader` with `collate_fn=pad_list_data_collate` might solve this problem "
                 + "(check its documentation)."
             )
-        raise TypeError(re_str)
+        raise TypeError(re_str) from re
 
 
 def decollate_batch(batch, detach: bool = True):

monai/transforms/inverse_batch_transform.py

@@ -99,7 +99,7 @@ def __call__(self, data: Dict[str, Any]) -> Any:
             re_str = str(re)
             if "equal size" in re_str:
                 re_str += "\nMONAI hint: try creating `BatchInverseTransform` with `collate_fn=lambda x: x`."
-            raise RuntimeError(re_str)
+            raise RuntimeError(re_str) from re
 
 
 class Decollated(MapTransform):

monai/utils/aliases.py

@@ -70,8 +70,8 @@ def resolve_name(name):
         try:
             mod = importlib.import_module(modname)
             obj = getattr(mod, declname, None)
-        except ModuleNotFoundError:
-            raise ValueError(f"Module {modname!r} not found.")
+        except ModuleNotFoundError as not_found_err:
+            raise ValueError(f"Module {modname!r} not found.") from not_found_err
 
         if obj is None:
             raise ValueError(f"Module {modname!r} does not have member {declname!r}.")

tests/utils.py

@@ -74,7 +74,7 @@ def test_pretrained_networks(network, input_param, device):
     try:
         net = network(**input_param).to(device)
     except (URLError, HTTPError, ContentTooShortError) as e:
-        raise unittest.SkipTest(e)
+        raise unittest.SkipTest(e) from e
     return net