Alchemy.Events.on_typing

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

on_typing(func)

(macro)

Registers a handle triggering whenever a user starts typing in a channel.

args : snowflake, snowflake, Integer

Receives the id of the user, the channel, and a timestamp (unix seconds) of the typing event.