A simple way to write a deep external_auth construct requires more documentation

[olevole]

We can write a custom external_auth configuration via @master_external_auth.to_yaml in erb. I understand the construction when we write something simple, e.g: { key => 'val' }. However I can not imagine how I can get the next piece of configuration as a result:

external_auth:
  pam:
    thatch:
      - .*
      - '@wheel'
      - '@runner'
      - '@jobs'
      ...

Can you add an example for such a case? It may be useful to be able to add custom inline 'as-is' configuration ( in addition to the ability to include custom user configuration file)