json:{
  "epub_version": "2", 
  "no_default_epub_cover": true, 
  "epub_inline_toc": false, 
  "dont_split_on_page_breaks": false, 
  "no_svg_cover": true, 
  "preserve_cover_aspect_ratio": false, 
  "toc_title": null, 
  "epub_flatten": false, 
  "flow_size": 260, 
  "epub_toc_at_end": false
}