python2 与python3的变化
1 写文件如果是bytes类型的话,打开文件 open参数设置为wb
2 python2 默认包import是相对路径,python3是绝对路径
3 python3的dict没有has_key方法,用in
4 map()
in Python 3 is a generator function, which is not serializeable in JSON. You can make it serializeable by converting it to a list
5