@type t() :: %LettaAPI.Model.MessageCreate{
  batch_item_id: String.t() | nil,
  content: LettaAPI.Model.Content4.t(),
  group_id: String.t() | nil,
  name: String.t() | nil,
  otid: String.t() | nil,
  role: String.t(),
  sender_id: String.t() | nil
}