type (_, _, _) t =
  1. | Arity1 : ('a -> unit, 'a -> 'r option, 'r) t
  2. | Arity2 : ('a -> 'b -> unit, 'a -> 'b -> 'r option, 'r) t
  3. | Arity3 : ('a -> 'b -> 'c -> unit, 'a -> 'b -> 'c -> 'r option, 'r) t
  4. | Arity4 : ('a -> 'b -> 'c -> 'd -> unit, 'a -> 'b -> 'c -> 'd -> 'r option, 'r) t
val sexp_of_t : ('v_x__001_ -> Ppx_sexp_conv_lib.Sexp.t) -> ('v_x__002_ -> Ppx_sexp_conv_lib.Sexp.t) -> ('v_x__003_ -> Ppx_sexp_conv_lib.Sexp.t) -> ('v_x__001_, 'v_x__002_, 'v_x__003_) t -> Ppx_sexp_conv_lib.Sexp.t