fix yaml dump of paths

            return yaml.safe_load(fp)

    def _dump_yaml(self, cfg: dict):

        """convert objects to to strings to avoid YAML dump as object"""

        """convert Path objects to strings to avoid YAML dump as object"""

        cfg = deepcopy(cfg)

        def format(d: dict):

            for k, v in d.items():

                if isinstance(v, dict):

                    format(v)

                else:

                elif isinstance(v, Path):

                    d[k] = str(v)

        format(cfg)

    def to_file(self, outfile: str|Path):

        to_dump = self._dump_yaml({k:v for k, v in self.__dict__.items() if k in self._dump_keys})

        with open(outfile, "w") as f:

            yaml.safe_dump(to_dump, f)

            yaml.dump(to_dump, f)

    def _validate_file_cfg(self, cfg: dict, use_windows_codec_binaries: bool):

        """ensure configuration contains required keys"""