@type t() :: %Inttegro.MessageTemplates.MessageTemplateVariable{
  about: String.t() | nil,
  default: term() | nil,
  items: [Inttegro.MessageTemplates.MessageTemplateVariableItem.t()] | nil,
  name: String.t(),
  required: boolean(),
  type: Inttegro.MessageTemplates.MessageTemplateVariableType.t()
}