[docs] Python docs as epub fail to convert

[Florian Batschi]

Hi,

just a short info:

I've downloaded the Python documentation in epub format and was trying
to convert it to .mobi (so as to use it on the Kindle). I used several
converters (including calibre, zamzar and multiple others) and all
failed doing so. They simply stalled and could not complete the conversion.

I think there is an issue with the epub, as all converters fail.

Maybe just a suggestion.

Greetings
Florian