setup.py for installing into a IPython system folder

setup.py

from distutils.command.install import install
from distutils.core import setup
import os.path
import json
import sys

kernel_json = {
    "argv": [sys.executable, 
	     "-m", "calico_scheme_kernel", 
	     "-f", "{connection_file}"],
    "display_name": "Scheme",
    "language": "scheme"
}

class install_with_kernelspec(install):
    def run(self):
        install.run(self)

        #os.system("ipython kernelspec install --system"
        from IPython.kernel.kernelspec import KernelSpecManager
        from IPython.utils.path import ensure_dir_exists
        if install_in_system:
            destdir = KernelSpecManager().kernel_dirs[0]
            # make sure that it exists
            if not os.path.exists(destdir):
                os.mkdir(destdir)
            destdir = os.path.join(destdir, 'calico_scheme_kernel')
            if not os.path.exists(destdir):
                os.mkdir(destdir)
        else:
            destdir = os.path.join(KernelSpecManager().user_kernel_dir, 
                                   'calico_scheme_kernel')
        ensure_dir_exists(destdir)
        with open(os.path.join(destdir, 'kernel.json'), 'w') as f:
            json.dump(kernel_json, f, sort_keys=True)

svem_flag = '--single-version-externally-managed'
if svem_flag in sys.argv:
    # Die, setuptools, die.
    sys.argv.remove(svem_flag)

system_flag = '--system'
if system_flag in sys.argv:
    sys.argv.remove(system_flag)
    install_in_system = True
else:
    install_in_system = False

setup(name='calico_scheme_kernel',
      version='0.2.6',
      description='A Scheme kernel for IPython',
      url="https://bitbucket.org/ipre/calico/src/master/src/calico_scheme_kernel/",
      long_description="A Scheme kernel for IPython",
      author='Douglas Blank',
      author_email='doug.blank@gmail.com',
      py_modules=['calico_scheme_kernel'],
      install_requires=["metakernel"],
      cmdclass={'install': install_with_kernelspec},
      classifiers = [
          'Framework :: IPython',
          'License :: OSI Approved :: BSD License',
          'Programming Language :: Python :: 3',
          'Programming Language :: Python :: 2',
          'Topic :: System :: Shells',
      ]
)