Update apply_func.py

The name Batch is no longer located under torchtext.data
--Error message--
File "/home/daniel/py38/lib/python3.8/site-packages/pytorch_lightning/utilities/apply_func.py", line 25, in <module>                                                      
    from torchtext.data import Batch                                                  
ImportError: cannot import name 'Batch' from 'torchtext.data' (/home/daniel/py38/lib/p
ython3.8/site-packages/torchtext/data/__init__.py)
You can fix this by changing line line 28 to:
    from torchtext.legacy.data import Batch

Author: dbonner

pytorch_lightning/utilities/apply_func.py

@@ -17,6 +17,7 @@
 from copy import copy
 from functools import partial
 from typing import Any, Callable, Optional, Union
+from packaging import version
 
 import numpy as np
 import torch
@@ -25,7 +26,10 @@
 from pytorch_lightning.utilities.imports import _TORCHTEXT_AVAILABLE
 
 if _TORCHTEXT_AVAILABLE:
-    from torchtext.data import Batch
+    if version.parse(torchtext.__version__) < version.parse('0.9.0a0+036df73'):
+        from torchtext.data import Batch
+    else:
+        from torchtext.legacy.data import Batch
 else:
     Batch = type(None)