Nesting yaml anchors

This should not be this difficult.

Here’s what I’m trying that isn’t working. CILint complains, anyway.

.one: &one
  - echo one

.two: &two
  - echo two

.three: &three
  - *one
  - *two

build:
  stage: build
  script:
    - *three

What am I doing wrong? Or, more importantly, what’s the syntax for getting this right?

v13 ci lint does not complain about this construction. Sadly, I’m running v12.10.