getDefaultExtensions "epub"            = Set.fromList [Ext_raw_html,
                                                       Ext_native_divs,
                                                       Ext_native_spans,
                                                       Ext_epub_html_exts]
getDefaultExtensions "epub"            = Set.fromList [Ext_raw_html,
                                                       Ext_native_divs,
                                                       Ext_native_spans,
                                                       Ext_epub_html_exts]
getDefaultExtensions "epub"            = Set.fromList [Ext_raw_html,
                                                       Ext_native_divs,
                                                       Ext_native_spans,
                                                       Ext_epub_html_exts]