Validation problem with successive __many__

[teto]

my mail reader alot generates an invalid warning (unknown values bindings: thread)when loading a config like

[bindings]

[[threads]]

whose spec is here
https://github.com/pazz/alot/blob/08438d56ef695883f8beb8c7515b261015c676f0/alot/defaults/alot.rc.spec#L273

I believe there is a problem with configobj's validation due to the several many levels.
Losely related issue pazz/alot#1238 (comment) (mostly at the end)

[robdennis]

I admit I'm not 100% sure what the expected result here should be; I'm going to at look into it a bit