def annotated_frames(scribbles_data):
    """ Finds which frames have a scribble.

    # Arguments
        scribbles_data (dict): Scribble in the default format.

    # Returns
        list: Number of the frames that contain at least one scribble.
    """
    scribbles = scribbles_data['scribbles']
    frames_list = [i for i, s in enumerate(scribbles) if s]
    return frames_list