def _split_repo_url(url):
    """Split a repository URL into an org / repo combination."""
    if "github.com/" in url:
        end = url.split("github.com/")[-1]
        org, repo = end.split("/")[:2]
    else:
        raise ValueError(
            f"Currently Binder/JupyterHub repositories must be on GitHub, got {url}"
        )
    return org, repo