django序列化时间

具体代码：

import json,time,datetime

lis ={'time':datetime.date.today(),"username":"zhilei",'age':10,'sex':"female"}

class JsonCu(json.JSONEncoder):
    def default(self, field):
        print("字段:",field,type(field))
        if isinstance(field, datetime.datetime):
            return field.strftime('%Y-%m-%d %H:%M:%S')
        elif isinstance(field, datetime.date):
            return field.strftime('%Y-%m-%d')
        else:
            return json.JSONEncoder.default(self, field)

result = json.dumps(lis,cls=JsonCu)
print(result,type(result))