python2 存csv和中文处理 [Debug]

如题，存csv的dictionary里key和value必须是str而不是unicode，上代码：

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import csv

with open('names.csv', 'w') as csvfile:
    fieldnames = ['first_name', 'last_name']
    writer = csv.DictWriter(csvfile, fieldnames=fieldnames)

    writer.writeheader()
    writer.writerow({'first_name': 'Baked\n sddsd', 'last_name': 'Beans\tsdfsaf'})
    writer.writerow({'first_name': '😍 😍', 'last_name': 'Spam'})
    writer.writerow({'first_name': u'中文'.encode("utf-8"), 'last_name': 'Spam'}) #python2里的dict要存str而不是unicode，所以encode把unicode转成str

with open('names.csv') as csvfile:
     reader = csv.DictReader(csvfile)
     for row in reader:
        print(row['first_name'])