`val select_one : (module Core_kernel.Hashable.Common with type t = 'a) ‑> 'a Incr.t ‑> ('a ‑> bool Incr.t) Core_kernel.Staged.t`
`val select_one' : (module Core_kernel.Hashable.Common with type t = 'a) ‑> 'a option Incr.t ‑> ('a ‑> bool Incr.t) Core_kernel.Staged.t`
`val select_one_value : (module Core_kernel.Hashable.Common with type t = 'a) ‑> default:'b ‑> ('a * 'b) Incr.t ‑> ('a ‑> 'b Incr.t) Core_kernel.Staged.t`
`val select_one_value' : (module Core_kernel.Hashable.Common with type t = 'a) ‑> default:'b ‑> ('a * 'b) option Incr.t ‑> ('a ‑> 'b Incr.t) Core_kernel.Staged.t`
`val select_many : (module Core_kernel.Hashable.Common with type t = 'a) ‑> 'a list Incr.t ‑> ('a ‑> bool Incr.t) Core_kernel.Staged.t`
`val select_many_values : (module Core_kernel.Hashable.Common with type t = 'a) ‑> default:'b ‑> ('a * 'b) list Incr.t ‑> ('a ‑> 'b Incr.t) Core_kernel.Staged.t`