3.4 to 3.6 : how to log deprecation warning in a particular log file?


I am working on my migration from 3.4 to 3.6
As everything seems to be ok on my development platform , I want to set up a particular log file for the deprecation warnings.
Is that possible? For according to the cookbook, we can only use levels.

That would be the migration process easier.
Does anyone have a clue?