how can I add a cape-super-capf backend to completion-at-point-functions?

[haoisli9]

I want add a cape-super-capf backend to completion-at-point-functions, but still keep other backend in completion-at-point-functions list. I write this as:
(add-to-list 'completion-at-point-functions

'(cape-super-capf #'cape-dabbrev #'tabnine-completion-at-point))

but seems not work.

how can I get this?

Thanks.

[minad]

Duplicate #46.