def METHOD_NAME(self, sources: Optional[Iterable[Path]] = None, fail: bool = True):
    sources = sources or []
    if not self.directory.is_dir():
        raise Exception(f"Cannot access {self.tool} repository: {self.directory}")
    sources_ = [str(source) for source in sources] if sources else []
    return commands.run_command_remote(
        cmd=[self.tool, "new-sources"] + sources_,
        cwd=self.directory,
        error_message="Adding new sources failed:",
        print_live=True,
        fail=fail,
    ).success