sig
  type t =
      Bid_size
    | Bid_price
    | Ask_price
    | Ask_size
    | Last_price
    | Last_size
    | High_price
    | Low_price
    | Volume
    | Close_price
    | Bid_option
    | Ask_option
    | Last_option
    | Model_option
    | Open_price
    | Low_13_week
    | High_13_week
    | Low_26_week
    | High_26_week
    | Low_52_week
    | High_52_week
    | Avg_volume
    | Open_interest
    | Historical_volatility
    | Implied_volatility
    | Option_bid_exch
    | Option_ask_exch
    | Call_open_interest
    | Put_open_interest
    | Call_volume
    | Put_volume
    | Index_future_premium
    | Bid_exch
    | Ask_exch
    | Auction_volume
    | Auction_price
    | Auction_imbalance
    | Mark_price
    | Bid_efp
    | Ask_efp
    | Last_efp
    | Open_efp
    | High_efp
    | Low_efp
    | Close_efp
    | Last_timestamp
    | Shortable
    | Fundamental_ratios
    | Realtime_volume
    | Halted
    | Bid_yield
    | Ask_yield
    | Last_yield
    | Cust_option_comp
  val t_of_sexp : Sexplib.Sexp.t -> Response.Tick_string.Type.t
  val sexp_of_t : Response.Tick_string.Type.t -> Sexplib.Sexp.t
end