def METHOD_NAME(blocks, block, plain_text_list, to_string, index):
    for field in ["source", "embed", "caption"]:
        data = block["data"].get(field)
        if not data:
            return
        data = clean_text_data(data)
        if to_string:
            plain_text_list.append(strip_tags(data))
        else:
            blocks[index]["data"][field] = data