python字典嵌套字典的情况下找到某个key的value详解

#coding: utf-8
import types

#获取字典中的objkey对应的值，适用于字典嵌套
#dict:字典
#objkey:目标key
#default:找不到时返回的默认值
def dict_get(dict, objkey, default):
  tmp = dict
  for k,v in tmp.items():
    if k == objkey:
      return v
    else:
      if type(v) is types.DictType:
        ret = dict_get(v, objkey, default)
        if ret is not default:
          return ret
  return default

#如
dicttest={"result":{"code":"110002","msg":"设备设备序列号或验证码错误"}}
ret=dict_get(dicttest, 'msg', None)
print(ret)