Sort imports with isort.

This is the result of:

    $ isort --recursive examples templates transformers utils hubconf.py setup.py

examples/distillation/scripts/extract_distilbert.py

@@ -16,10 +16,13 @@
 Preprocessing script before training DistilBERT.
 Specific to BERT -> DistilBERT.
 """
-from transformers import BertForMaskedLM, RobertaForMaskedLM
-import torch
 import argparse
 
+import torch
+
+from transformers import BertForMaskedLM, RobertaForMaskedLM
+
+
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(
         description="Extraction some layers of the full BertForMaskedLM or RObertaForMaskedLM for Transfer Learned Distillation"