builds.tools.python: 3 documented, but not working

[FriedrichFroebel]

Details

• Read the Docs project URL: https://readthedocs.org/projects/pycaching/
• Build URL (if applicable): https://readthedocs.org/projects/pycaching/builds/22752032/
• Read the Docs username (if applicable): https://readthedocs.org/profiles/FriedrichFroebel/

Expected Result

build:
  os: ubuntu-22.04
  tools:
    python: 3

should work or throw a meaningful error message that the Python version should be a string.

Actual Result

I am told that 3 is an invalid value, while the value itself occurs inside the list of allowed values:

Problem in your project's configuration. Invalid configuration option "build.tools.python": expected one of (2.7, 3.6, 3.7, 3.8, 3.9, 3.10, 3.11, 3.12, 3, miniconda3-4.7, mambaforge-4.10, mambaforge-22.9), got 3

Only https://docs.readthedocs.io/en/stable/config-file/v2.html#build-tools-python seems to indicate that the value needs to be a string.

[stsewd]

Hi, you need to use quotes to force the value to be string, see #9719. Sorry about the confusion.