def METHOD_NAME():
    # create coco json
    coco = dict()
    coco['images'] = []
    coco['type'] = 'instances'
    coco['annotations'] = []
    coco['categories'] = []
    # voc classes
    voc_class = [
        'aeroplane', 'bicycle', 'bird', 'boat', 'bottle', 'bus', 'car', 'cat',
        'chair', 'cow', 'diningtable', 'dog', 'horse', 'motorbike', 'person',
        'pottedplant', 'sheep', 'sofa', 'train', 'tvmonitor'
    ]
    # init json categories
    image_set = set()
    class_set = dict()
    for cat_id, cat_name in enumerate(voc_class):
        cat_item = dict()
        cat_item['supercategory'] = 'none'
        cat_item['id'] = cat_id
        cat_item['name'] = cat_name
        coco['categories'].append(cat_item)
        class_set[cat_name] = cat_id
    return coco, class_set, image_set