old_contents: import setuptools
  
  setuptools.setup(
      name="torchdiffeq",
      version="0.0.1",
      author="Ricky Tian Qi Chen",
      author_email="rtqichen@cs.toronto.edu",
      description="ODE solvers and adjoint sensitivity analysis in PyTorch.",
      url="https://github.com/rtqichen/torchdiffeq",
      packages=['torchdiffeq'],
      install_requires=['torch>=0.4.1'],
      classifiers=(
          "Programming Language :: Python :: 3"),)
  
new_contents: import setuptools
  
  setuptools.setup(
      name="torchdiffeq",
      version="0.0.1",
      author="Ricky Tian Qi Chen",
      author_email="rtqichen@cs.toronto.edu",
      description="ODE solvers and adjoint sensitivity analysis in PyTorch.",
      url="https://github.com/rtqichen/torchdiffeq",
      packages=['torchdiffeq', 'torchdiffeq._impl'],
      install_requires=['torch>=0.4.1'],
      classifiers=(
          "Programming Language :: Python :: 3"),)
  
subject: add torchdiffeq._impl package to setup.py