sig
type ('a, 'b, 'c) writer =
'a Type_class.writer0 -> ('b, 'c) Type_class.S1.writer
type ('a, 'b, 'c) reader =
'a Type_class.reader0 -> ('b, 'c) Type_class.S1.reader
type ('a, 'b, 'c) t = 'a Type_class.t0 -> ('b, 'c) Type_class.S1.t
end