t() :: %ExFtx.ExpiredFuture{
  ask: number(),
  bid: number(),
  description: String.t(),
  enabled: boolean(),
  expired: boolean(),
  expiry: String.t(),
  expiry_description: String.t(),
  group: String.t(),
  imf_factor: number(),
  index: number(),
  last: number(),
  lower_bound: number(),
  margin_price: number(),
  mark: number(),
  move_start: term(),
  name: String.t(),
  perpetual: boolean(),
  position_limit_weight: number(),
  post_only: boolean(),
  price_increment: number(),
  size_increment: number(),
  type: String.t(),
  underlying: String.t(),
  upper_bound: number()
}