Alchemy.Cache.guild_id

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

guild_id(channel_id)

Specs

guild_id(snowflake()) :: {:ok, snowflake()} | {:error, String.t()}

Gets the corresponding guild_id for a channel.

In case the channel guild can't be found, :none will be returned.

This is useful when the guild_id is needed for some kind of task, but there's no need for getting the whole struct. Because of how the registry is set up, getting the entire guild requires a whole extra step, that passes through this one anyways.