t() :: %ExFtx.Future{
  ask: number(),
  bid: number(),
  change_1h: number(),
  change_24h: number(),
  change_bod: number(),
  description: String.t(),
  enabled: boolean(),
  expired: boolean(),
  expiry: String.t(),
  imf_factor: number(),
  index: number(),
  last: number(),
  lower_bound: number(),
  mark: number(),
  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(),
  volume: number(),
  volume_usd_24h: number()
}