Nightlies are failing because of this one

Check it out https://gitlab.idiap.ch/bob/bob.nightlies/-/jobs/173437

======================================================================
ERROR: test for the DltResNet architecture
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/scratch/builds/bob/bob.nightlies/miniconda/conda-bld/bob.learn.pytorch_1568687631902/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold/lib/python3.7/site-packages/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "/scratch/builds/bob/bob.nightlies/miniconda/conda-bld/bob.learn.pytorch_1568687631902/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold/lib/python3.7/site-packages/bob/learn/pytorch/test/test_audio_extractor.py", line 19, in test_drn
    from bob.learn.pytorch.preprocessor.audio import DltResNetExtractor
  File "/scratch/builds/bob/bob.nightlies/miniconda/conda-bld/bob.learn.pytorch_1568687631902/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold/lib/python3.7/site-packages/bob/learn/pytorch/preprocessor/audio/__init__.py", line 1, in <module>
    from .DltResNet import DltResNetExtractor
  File "/scratch/builds/bob/bob.nightlies/miniconda/conda-bld/bob.learn.pytorch_1568687631902/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold/lib/python3.7/site-packages/bob/learn/pytorch/preprocessor/audio/DltResNet.py", line 151
    input_var = torch.autograd.Variable(torch.Tensor(in_batch).unsqueeze(1).cuda(async=True))
                                                                                     ^
SyntaxError: invalid syntax

======================================================================
ERROR: test for the ResNet architecture
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/scratch/builds/bob/bob.nightlies/miniconda/conda-bld/bob.learn.pytorch_1568687631902/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold/lib/python3.7/site-packages/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "/scratch/builds/bob/bob.nightlies/miniconda/conda-bld/bob.learn.pytorch_1568687631902/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold/lib/python3.7/site-packages/bob/learn/pytorch/test/test_audio_extractor.py", line 35, in test_rn
    from bob.learn.pytorch.preprocessor.audio import DltResNetExtractor
  File "/scratch/builds/bob/bob.nightlies/miniconda/conda-bld/bob.learn.pytorch_1568687631902/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold/lib/python3.7/site-packages/bob/learn/pytorch/preprocessor/audio/__init__.py", line 1, in <module>
    from .DltResNet import DltResNetExtractor
  File "/scratch/builds/bob/bob.nightlies/miniconda/conda-bld/bob.learn.pytorch_1568687631902/_test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold/lib/python3.7/site-packages/bob/learn/pytorch/preprocessor/audio/DltResNet.py", line 151
    input_var = torch.autograd.Variable(torch.Tensor(in_batch).unsqueeze(1).cuda(async=True))
                                                                                     ^
SyntaxError: invalid syntax

Can someone have a look at it, please? ping @heusch @ageorge

Thanks