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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def ensure_sphinx_astropy_installed():
 """ Make sure that sphinx-astropy is available, installing it temporarily if not. This returns the available version of sphinx-astropy as well as any paths that should be added to sys.path for sphinx-astropy to be available. """

    # We've split out the Sphinx part of astropy-helpers into sphinx-astropy
    # but we want it to be auto-installed seamlessly for anyone using
    # build_docs. We check if it's already installed, and if not, we install
    # it to a local .eggs directory and add the eggs to the path (these
    # have to each be added to the path, we can't add them by simply adding
    # .eggs to the path)
    sys_path_inserts = []
    sphinx_astropy_version = None
    try:
        from sphinx_astropy import __version__ as sphinx_astropy_version  # noqa
    except ImportError:

        from setuptools import Distribution
        dist = Distribution()

        # Numpydoc 0.9.0 requires sphinx 1.6+, we can limit the version here
        # until we also makes our minimum required version Sphinx 1.6
        if SPHINX_LT_16:
            dist.fetch_build_eggs('numpydoc<0.9')

        # This egg build doesn't respect python_requires, not aware of
        # pre-releases. We know that mpl 3.1+ requires Python 3.6+, so this
        # ugly workaround takes care of it until there is a solution for
        # https://github.com/astropy/astropy-helpers/issues/462
        if LooseVersion(sys.version) < LooseVersion('3.6'):
            dist.fetch_build_eggs('matplotlib<3.1')

        eggs = dist.fetch_build_eggs('sphinx-astropy')

        # Find out the version of sphinx-astropy if possible. For some old
        # setuptools version, eggs will be None even if sphinx-astropy was
        # successfully installed.
        if eggs is not None:
            for egg in eggs:
                if egg.project_name == 'sphinx-astropy':
                    sphinx_astropy_version = egg.parsed_version.public
                    break

        eggs_path = os.path.abspath('.eggs')
        for egg in glob.glob(os.path.join(eggs_path, '*.egg')):
            sys_path_inserts.append(egg)

    return sphinx_astropy_version, sys_path_inserts