old_contents: """
  PyTorch integration.
  """
  from phi import math
  from .torch_backend import TorchBackend
  
  TORCH_BACKEND = TorchBackend()
  math.DYNAMIC_BACKEND.add_backend(TORCH_BACKEND)
  
new_contents: """
  PyTorch integration.
  """
  from phi import math
  from .torch_backend import TorchBackend
  
  TORCH_BACKEND = TorchBackend()
  math.DYNAMIC_BACKEND.add_backend(TORCH_BACKEND)
  math.DYNAMIC_BACKEND.default_backend = TORCH_BACKEND
  
subject: fix torch default for phiflow 2