`type t`
`val create : ?enabled:bool -> label -> t`

create a new message handle with label t . * Printing is disabled per default

`val eprintf : ?raw:bool -> t -> ('a, unit, string, unit) Stdlib.format4 -> 'a`

Print the message on `stderr` if the Util module has been * set to verbose using the function `make_verbose` and * either the handle `t` is enable or all handles were enabled with * the function `all_enabled`

`val enable : label -> unit`

`enable l` the handle with label `l`

`val disable : label -> unit`

`disable l` the handle with label `l`

`val all_disabled : unit -> unit`

disable all handles in the module

`val all_enabled : unit -> unit`

enable all handles in the module

`val avalaible : unit -> label list`

return the list of all labels known to the module

`val is_enabled : label -> bool`