Alchemy.Events.on_role_delete

You're seeing just the macro on_role_delete, go back to Alchemy.Events module for more information.
Link to this macro

on_role_delete(func)

(macro)

Registers a handle triggering whenever a role gets deleted from a guild.

args : snowflake, snowflake

Receives the id of the role that was deleted, and the id of the guild it was deleted from.