def get_dir_from_zipfile(zip_file, fallback=None):
    """Return the name of the root folder in a zip file.

    :param zip_file: a :class:`zipfile.ZipFile` instance.
    :param fallback: if `None`, the name of the zip file is used. This is
        returned if the zip file contains more than one top-level directory,
        or none at all.
    """
    fallback = fallback or zip_file.filename
    directories = [name for name in zip_file.namelist() if name.endswith("/")
                   and len(PurePath(name).parts) == 1]
    return fallback if len(directories) > 1 else directories[0]
def commit_and_push(repo_dir, day):
    subprocess.check_call(
        ["git", "config", "--global", "user.email", "u1test+m-o@canonical.com"]
    )
    subprocess.check_call(["git", "config", "--global", "user.name", "snappy-m-o"])

    subprocess.check_call(["git", "-C", repo_dir, "add", "--all"])
    subprocess.check_call(
        [
            "git",
            "-C",
            repo_dir,
            "commit",
            "--message",
            "Add the results for {}".format(day),
        ]
    )

    subprocess.check_call(
        [
            "git",
            "-C",
            repo_dir,
            "push",
            "https://{GH_TOKEN}@github.com/elopio/autopkgtest-results.git".format(
                GH_TOKEN=os.environ.get("GH_TOKEN_PPA_AUTOPKGTEST_RESULTS")
            ),
        ]
    )