* improved docs for callbacks
* class references
* make doctest pass
* doctests
* fix lines too long
* fix line too long
* fix permission error in doctest
* Apply suggestions from code review
Co-Authored-By: Jirka Borovec <Borda@users.noreply.github.com>
* fix doctest
* fix default
Co-authored-by: Jirka Borovec <Borda@users.noreply.github.com>