[Misc] Black auto fix. (#4642)

* [Misc] Black auto fix.

* sort
Co-authored-by: Steve <ubuntu@ip-172-31-34-29.ap-northeast-1.compute.internal>

examples/pytorch/diffpool/model/dgl_layers/__init__.py

-from .gnn import GraphSage, GraphSageLayer, DiffPoolBatchedGraphLayer
\ No newline at end of file
+from .gnn import DiffPoolBatchedGraphLayer, GraphSage, GraphSageLayer

examples/pytorch/diffpool/model/tensorized_layers/__init__.py

 from .diffpool import BatchedDiffPool
-from .graphsage import BatchedGraphSAGE
\ No newline at end of file
+from .graphsage import BatchedGraphSAGE