If I have said yaml file:

org-lists:
  ea-orgs: [
    1, # test-org
  ]
  ga-orgs: [
    2, # customer-2
    3, # customer-3
    4, # customer-4
  ]

It completely removes the comments after I do a simple load and dump:

import ruamel.yaml

def format_yaml(filename: str) -> None:
    yaml = ruamel.yaml.YAML()
    yaml.preserve_quotes = True
    yaml.indent(mapping=2, sequence=4, offset=2)

    with open(filename, "r") as file:
        data = yaml.load(file)

    with open(filename, "w") as file:
        yaml.dump(data, file)

Has anyone ran into a similar issue, and how did you work around it?

I tried changing the list structure to look like:

org-lists:
  ea-orgs: 
    - 1 # test-org

and that will preserve the comments, but I prefer the square brackets.

I’ve also tried:

yaml.default_flow_style = None