[Question]REPL in docker or singularity images

[pirocv]

Hi. Thanks for a great plugin!
I’m facing a problem when I’d like to use R in docker or singularity image as REPL.
I tried
let g:neoterm_repl_r=‘singularity exec ~/singularity_img/saige_0.43.2.sif R’
or
let g:neoterm_repl_r=‘/path/to/singularity exec /path/to/singularity_img/saige_0.43.2.sif R’
in init.vim file. But they did not work.

The following command lauches R in singularity image and works fine.
singularity exec ~/singularity_img/saige_0.43.2.sif R

I’m new to neoterm, so I’m not sure I’m asking a appropriate question.
Do you have any suggestions?
I'm using nvim 0.4.4.
Many thanks in advance.