calibre html5lib breakage

calibre html5lib breakage

$ ebook-edit
Traceback (most recent call last):
  File "/nix/store/4vdpy5kn79wiz6x0bpddbf7g5zdvm6ac-calibre-3.1.1/bin/..ebook-edit-wrapped-wrapped", line 20, in <module>
    sys.exit(ebook_edit())
  File "/nix/store/4vdpy5kn79wiz6x0bpddbf7g5zdvm6ac-calibre-3.1.1/lib/calibre/calibre/gui_launch.py", line 97, in ebook_edit
    main(args)
  File "/nix/store/4vdpy5kn79wiz6x0bpddbf7g5zdvm6ac-calibre-3.1.1/lib/calibre/calibre/gui2/tweak_book/main.py", line 104, in main
    _run(args)
  File "/nix/store/4vdpy5kn79wiz6x0bpddbf7g5zdvm6ac-calibre-3.1.1/lib/calibre/calibre/gui2/tweak_book/main.py", line 73, in _run
    from calibre.gui2.tweak_book.ui import Main
  File "/nix/store/4vdpy5kn79wiz6x0bpddbf7g5zdvm6ac-calibre-3.1.1/lib/calibre/calibre/gui2/tweak_book/ui.py", line 28, in <module>
    from calibre.gui2.tweak_book.file_list import FileListWidget
  File "/nix/store/4vdpy5kn79wiz6x0bpddbf7g5zdvm6ac-calibre-3.1.1/lib/calibre/calibre/gui2/tweak_book/file_list.py", line 22, in <module>
    from calibre.ebooks.oeb.polish.container import OEB_FONTS, guess_type
  File "/nix/store/4vdpy5kn79wiz6x0bpddbf7g5zdvm6ac-calibre-3.1.1/lib/calibre/calibre/ebooks/oeb/polish/container.py", line 49, in <module>
    from calibre.ebooks.oeb.polish.parsing import parse as parse_html_tweak
  File "/nix/store/4vdpy5kn79wiz6x0bpddbf7g5zdvm6ac-calibre-3.1.1/lib/calibre/calibre/ebooks/oeb/polish/parsing.py", line 16, in <module>
    from html5lib.treebuilders._base import TreeBuilder as BaseTreeBuilder
ImportError: No module named _base