Python正则表达式提取车牌号

car_search = r'[京津沪渝冀豫云辽黑湘皖鲁新苏浙赣鄂桂甘晋蒙陕吉闽贵粤青藏川宁台琼使领军北南成广沈济空海]{1}[A-Z]{1}[A-Z0-9]{4}[A-Z0-9挂领学警港澳]{1}(?!\d)'
text="我的车牌号是***"  #需要抽取的文本
def car_ID_extract(text):
    all_car_id = re.findall(car_search, text)
    car_id = []
    car_id1 = ""
    if all_car_id:
        for i in all_car_id:
            if not i in car_id:
                car_id.append(i)
        for i in car_id:
            car_id1 = car_id1 + ' ' + "".join(tuple(i))   #将列表转字符串
    return car_id1            #返回字符串
print(car_ID_extract(text))