def get_deployment_timestamp():
    """Returns a unique string represeting the current deployment.

    Used for busting caches.
    """
    # TODO: Support other deployment situations.
    if os.environ.get('SERVER_SOFTWARE', '').startswith('Google App Engine'):
        version_id = os.environ.get('CURRENT_VERSION_ID')
        major_version, timestamp = version_id.split('.', 1)
        return timestamp
    return 'test'
Returns a unique string represeting the current deployment.

    Used for busting caches.