anchor.diff:  
     meta = {
       homepage = "https://github.com/ocaml-community/sedlex";
  +    changelog = "https://github.com/ocaml-community/sedlex/raw/v${version}/CHANGES";
       description = "An OCaml lexer generator for Unicode";
       license = lib.licenses.mit;
       maintainers = [ lib.maintainers.marsam ];
  
positive.code: in
  buildDunePackage rec {
    pname = "sedlex";
    version = "2.2";
  
    useDune2 = true;
  
  
negative.code: , buildDunePackage
  , ocaml
  , gen
  , ppxlib
  , uchar
  }:
  
  if lib.versionOlder ocaml.version "4.08"
  then throw "sedlex is not available for OCaml ${ocaml.version}"
  else
  
  