FIELD_CHOICES in values.yaml

[AndMrzv]

I've been trying to add an extra status option (#8054) via helm chart values.yaml file.
Tried

fieldChoices:
  'dcim.Site.status+':
    - [foo, Foo, red]

more quotes, less quotes, double quotes, parentheses, with no "-", breaking the list of status parameters into lines, all passing YAML linting - zero effect. So I wonder what it should look like to work properly.
Other simpler settings work fine. Running v3.2.5.

[AndMrzv]

Wait, my templates are too ancient for that.