>>   Value: (nil
>>    (#("   " 0 3
>>       (fontified t))
>>     . 12)
>>    (#<marker at 12 in foo.py> . -2)
>>    (#<marker at 12 in foo.py> . -2)
>>    (#<marker in no buffer> . -3)
>>    (#<marker in no buffer> . -2)
>>    (t 20985 26927 0 0))

> Oh, right. That would be good as well. At least as good as option 1.
> So I'd go with whichever of option 1 or 2 is simpler.

Attached is the new patch to solve this, implementing option 2 and
incorporating your feedback.