I was able to save SQL in beauty way based on question Save SQL to YAML as is.
Now, I should resolve issue with saving order in YAML as was before loading. So, I had YAML config as:
app:
....
conf:
sql:
....
mapping:
....
filters:
....
Once I save with ruamel.yaml I got random order saving as example below:
filters:
....
conf:
mapping:
....
sql:
....
app:
....
How can I save the keys of YAML-file as was loaded?