text: from distutils.core import setup
  import skyfield  # safe, because __init__.py contains no import statements
  
  extras = {
      'tests': [
          # TODO: add assay
          'pytz',
      ],
  }
  
  setup(
      name='skyfield',
      version=skyfield.__version__,
      description=skyfield.__doc__.split('\n', 1)[0],
      long_description=open('README.rst', 'rb').read().decode('utf-8'),
      license='MIT',
      author='Brandon Rhodes',
      author_email='brandon@rhodesmill.org',
      url='http://github.com/brandon-rhodes/python-skyfield/',
      classifiers=[
          'Development Status :: 5 - Production/Stable',
          'Intended Audience :: Developers',
          'Intended Audience :: Education',
          'Intended Audience :: Science/Research',
          'License :: OSI Approved :: MIT License',
          'Programming Language :: Python :: 2.6',
          'Programming Language :: Python :: 2.7',
          'Programming Language :: Python :: 3.3',
          'Programming Language :: Python :: 3.4',
          'Programming Language :: Python :: 3.5',
          'Programming Language :: Python :: 3.6',
          'Topic :: Scientific/Engineering :: Astronomy',
          ],
      packages=[
          'skyfield',
          'skyfield.data',
          'skyfield.tests',
          ],
      package_data = {
          'skyfield': ['documentation/*.rst'],
          'skyfield.data': ['*.npy', '*.npz'],
          'skyfield.tests': ['data/*'],
          },
      install_requires=[
          'jplephem>=2.3',
          'numpy',
          'sgp4>=1.4',
          ],
      extras_require=extras,          # support "pip install skyfield[tests]"
  )
  