sig
type t =
[ `Ask
| `Bid
| `Bid_ask
| `Historical_volatility
| `Implied_volatility
| `Midpoint
| `Option_volume
| `Trades ]
val of_string : string -> t
val to_string : t -> string
val t_of_sexp : Sexplib.Sexp.t -> Query.History.Tick_type.t
val __t_of_sexp__ : Sexplib.Sexp.t -> Query.History.Tick_type.t
val sexp_of_t : Query.History.Tick_type.t -> Sexplib.Sexp.t
end