def merge_coco_results(existing_coco_results, new_coco_results, image_id_offset):
    """ Merges the two given coco result dicts into one.

    :param existing_coco_results: A dict describing the first coco results.
    :param new_coco_results: A dict describing the second coco results.
    :return: A dict containing the merged coco results.
    """

    for res in new_coco_results:
        res['image_id'] += image_id_offset
    existing_coco_results += new_coco_results
    
    return existing_coco_results