t() :: %ExDeltaExchange.Index{
  config: map(),
  constituent_exchanges: list(),
  constituent_indices: list(),
  description: String.t(),
  health_interval: non_neg_integer(),
  id: non_neg_integer(),
  impact_size: String.t(),
  index_type: String.t(),
  is_composite: boolean(),
  price_method: String.t(),
  quoting_asset_id: non_neg_integer(),
  symbol: String.t(),
  tick_size: String.t(),
  underlying_asset_id: non_neg_integer()
}