define hash on duration
Merge pull request #17160 from lsylvester/duration-hash

define hash on duration
add notes for `define_model_callbacks` [ci skip]
Merge pull request #17167 from kuldeepaggarwal/doc-define_model_callbacks

add notes for `define_model_callbacks`
Fix typo
Merge pull request #17168 from jwworth/task/fix_typo

Fix typo [ci skip]