let string_to_item ?filename ?(tags=default_tags) () =
let name = sprintf "gff_parser:%s" Option.(value ~default:"<>" filename) in
let pedantic = List.mem tags `pedantic in
let version =
List.find_map tags (function `version v -> Some v | _ -> None) in
let next = next ~pedantic ?version in
Biocaml_transform.Line_oriented.make_merge_error
~name ?filename ~next ()