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 call_vision_api(image_filename, api_keys):
    api_key = api_keys['microsoft']
    post_url = "https://api.projectoxford.ai/vision/v1.0/analyze?visualFeatures=Categories,Tags,Description,Faces,ImageType,Color,Adult&subscription-key=" + api_key

    image_data = open(image_filename, 'rb').read()
    result = requests.post(post_url, data=image_data, headers={'Content-Type': 'application/octet-stream'})
    result.raise_for_status()

    return result.text