You're seeing just the function bulk_delete_messages, go back to Nostrum.Api module for more information.
Link to this function

bulk_delete_messages(channel_id, messages, filter \\ true)

View Source


bulk_delete_messages(integer(), [], boolean()) ::
  error() | {:ok}

Deletes multiple messages from a channel.

messages is a list of that you wish to delete. When given more than 100 messages, this function will chunk the given message list into blocks of 100 and send them off to the API. It will stop deleting on the first error that occurs. Keep in mind that deleting thousands of messages will take a pretty long time and it may be proper to just delete the channel you want to bulk delete in and recreate it.

This method can only delete messages sent within the last two weeks. Filter is an optional parameter that specifies whether messages sent over two weeks ago should be filtered out; defaults to true.