Alchemy.Client.start

You're seeing just the function start, go back to Alchemy.Client module for more information.
Link to this function

start(token, options \\ [])

Specs

start(token(), [{:selfbot, snowflake()}]) :: {:ok, pid()}

Starts up a new Client with the given token.

An optional selfbot: id can be passed, indiciating that you're using a user token instead of a normal bot token. SelfBots will only respond to themselves, and certain functionalities of the API may not work as well as for normal bots.