def setup(app):
    """When used for sphinx extension."""
    global _is_sphinx
    _is_sphinx = True
    app.add_config_value('no_underscore_emphasis', False, 'env')
    app.add_config_value('m2r_parse_relative_links', False, 'env')
    app.add_config_value('m2r_anonymous_references', False, 'env')
    app.add_config_value('m2r_disable_inline_math', False, 'env')
    app.add_source_parser('.md', M2RParser)
    app.add_directive('mdinclude', MdInclude)
    metadata = dict(
        version=__version__,
        parallel_read_safe=True,
        parallel_write_safe=True,
    )
    return metadata
When used for sphinx extension.