ocaml-deriving-ocsigen @0.3c: The implementation utils.ml does not match the interface utils.cmi

[ryandesign (Ryan Carsten Schmidt)]

​https://build.macports.org/builders/ports-10.13_x86_64-builder/builds/36739/steps/install-port/logs/stdio

File "utils.ml", line 1:
Error: The implementation utils.ml does not match the interface utils.cmi:
       Values do not match:
         val random_id : int -> bytes
       is not included in
         val random_id : int -> string
       File "utils.mli", line 70, characters 0-29: Expected declaration
       File "utils.ml", line 202, characters 4-13: Actual declaration
make[1]: *** [utils.cmo] Error 2