今日作业 day21

###第一题
import hashlib
import datetime
import os
import pickle

class MySQL:
    def __init__(self, host, port):
        self.id = self.create_id
        self.host = host
        self.port = port

    def create_id(self):
        m = hashlib.md5
        m.update(f'{datetime.datetime.now()}'.encode('utf8'))
        self.id = m.hexdigest()

    def save(self):
        if not self.is_exists:
            raise PermissionError('对象已存在!!')
        file_path = os.path.join(settings.DB_PATH, self.id)
        pickle.dump(self, open(file_path, 'wb'))

    def get_obj_by_id(id):
        file_path = os.path.join(settings.DB_PATH, id)
        return pickle.load(open(file_abspath,'rb'))###第一题
import hashlib
import dateti