python字符串.format

如果本身字符串中就用到了{}，再用format占位时会有问题 该如何解决呢

python格式化字符串的四种方式都在里面
https://www.zhihu.com/tardis/sogou/art/110406030

import json
a = [11,12]
re = 'UserMsg:{"request_type": "detect","request_number": 12345,"production_line_number": 1,"image": "xxx"}'
re = json.loads(re.replace('UserMsg:',''))
re['image'] = a[0]
print(re)

a="你好{}"+"{}".format("您好")