def METHOD_NAME(self, file_names):
    file_names_read = []
    for fname in always_iterable(file_names):
        if not os.path.exists(fname):
            continue
        metadata = {"source": f"file: {fname}"}
        if sys.version_info >= (3, 11):
            import tomllib
        else:
            import tomli as tomllib
        try:
            with open(fname, "rb") as fh:
                data = tomllib.load(fh)
        except tomllib.TOMLDecodeError as exc:
            warnings.warn(
                f"Could not load configuration file {fname} (invalid TOML: {exc})",
                stacklevel=2,
            )
        else:
            self.update(data, metadata=metadata)
            file_names_read.append(fname)
    return file_names_read