type log =
< f : 'a. int ->('a, unit, string, unit)Stdlib.format4->'a
; critical : 'a. ('a, unit, string, unit)Stdlib.format4->'a
; severe : 'a. ('a, unit, string, unit)Stdlib.format4->'a
; important : 'a. ('a, unit, string, unit)Stdlib.format4->'a
; info : 'a. ('a, unit, string, unit)Stdlib.format4->'a
; debug : 'a. ('a, unit, string, unit)Stdlib.format4->'a >