BatchEncoding.to with device with tests (#9584)

src/transformers/tokenization_utils_base.py

@@ -65,6 +65,12 @@ def _is_torch(x):
     return isinstance(x, torch.Tensor)
 
 
+def _is_torch_device(x):
+    import torch
+
+    return isinstance(x, torch.device)
+
+
 def _is_tensorflow(x):
     import tensorflow as tf
 
@@ -801,7 +807,7 @@ class BatchEncoding(UserDict):
         # This check catches things like APEX blindly calling "to" on all inputs to a module
         # Otherwise it passes the casts down and casts the LongTensor containing the token idxs
         # into a HalfTensor
-        if isinstance(device, str) or isinstance(device, torch.device) or isinstance(device, int):
+        if isinstance(device, str) or _is_torch_device(device) or isinstance(device, int):
             self.data = {k: v.to(device=device) for k, v in self.data.items()}
         else:
             logger.warning(