Make3.1-X
type ('a, 'd, 'e) t
val bind : ( 'a, 'd, 'e ) t -> f:( 'a -> ( 'b, 'd, 'e ) t ) -> ( 'b, 'd, 'e ) t
val map : [ `Define_using_bind | `Custom of ( 'a, 'd, 'e ) t -> f:( 'a -> 'b ) -> ( 'b, 'd, 'e ) t ]
val return : 'a -> ( 'a, _, _ ) t