This library provides utilities to apply custom damage to entities and players.
This library is deprecated as of Minecraft 1.20 with the introduction of the /damage command.
You can download it from here
or
You can build it from source using the beet
$ pip install beet mecha
$ git clone https://github.com/Smithed-MC/Libraries
$ cd Libraries/damage
$ beet -s 'meta.libraries = ["damage"]'