ResourceWarning shows up when doing multigpu graphbolt example

[TristonC]

Runs the example under dgl/examples/multigpu/graphbolt, it shows a bit annoying ResourceWarning.

 python node_classification.py --gpu 0,1,2,3,4,5,6,7

16it [00:01, 12.86it/s]
Epoch 00009 | Average Loss 1.1217 | Accuracy 0.6525 | Time 14.4035
Testing...
25it [00:02, 11.18it/s]/usr/lib/python3.10/tempfile.py:1008: ResourceWarning: Implicitly cleaning up <TemporaryDirectory '/tmp/tmpnqgx4sch'>
  _warnings.warn(warn_message, ResourceWarning)
27it [00:02, 11.99it/s]
Test Accuracy 0.6272
/usr/lib/python3.10/tempfile.py:1008: ResourceWarning: Implicitly cleaning up <TemporaryDirectory '/tmp/tmpns5n0f16'>
  _warnings.warn(warn_message, ResourceWarning)
/usr/lib/python3.10/tempfile.py:1008: ResourceWarning: Implicitly cleaning up <TemporaryDirectory '/tmp/tmp4sbe1b2l'>
  _warnings.warn(warn_message, ResourceWarning)
/usr/lib/python3.10/tempfile.py:1008: ResourceWarning: Implicitly cleaning up <TemporaryDirectory '/tmp/tmpgtm6h_av'>
  _warnings.warn(warn_message, ResourceWarning)
/usr/lib/python3.10/tempfile.py:1008: ResourceWarning: Implicitly cleaning up <TemporaryDirectory '/tmp/tmpbebuzjfx'>
  _warnings.warn(warn_message, ResourceWarning)
/usr/lib/python3.10/tempfile.py:1008: ResourceWarning: Implicitly cleaning up <TemporaryDirectory '/tmp/tmpnp2bys02'>
  _warnings.warn(warn_message, ResourceWarning)
/usr/lib/python3.10/tempfile.py:1008: ResourceWarning: Implicitly cleaning up <TemporaryDirectory '/tmp/tmp0mbq_2c8'>
  _warnings.warn(warn_message, ResourceWarning)
/usr/lib/python3.10/tempfile.py:1008: ResourceWarning: Implicitly cleaning up <TemporaryDirectory '/tmp/tmpcirawy77'>
  _warnings.warn(warn_message, ResourceWarning)