Python发送邮件的类

综合网上查到的内容，写的Python发送邮件的类。附件部分还没写好，主要是附件的文件名部分还不对。
#!/usr/bin/env python
# coding:utf-8
import email
import smtplib
class Mailer:
def __init__(self, smtp_host, smtp_user, smtp_passwd, smtp_port = 25) :
self.smtp_host = smtp_host
self.smtp_user = smtp_user
self.smtp_passwd = smtp_passwd
self.smtp_port = smtp_port
self.mail = email.MIMEMultipart.MIMEMultipart('main')
self.attachments = []
def mailfrom(self, mail_from) :
self._from = mail_from
self.mail['from'] = mail_from

def mailto(self, mail_to) :
"""
mail_to : comma separated emails or a list
"""

if type(mail_to) == list:
self.mail['to'] = ','.join(mail_to)
self._to = mail_to
elif type(mail_to) == str :
self.mail['to'] = mail_to
if mail_to.find(',') > 0 :
self._to = [s.strip() for s in mail_to.split(',')]
else :
self._to = mail_to
else :
raise Exception('invalid mail to')
def mailsubject(self, mail_subject) :
self.mail['subject'] = mail_subject

def mailbody(self, mail_body) :
self.mail.attach(email.MIMEText.MIMEText(mail_body, 'plain', 'utf-8'))

def addattach(self, filepath, mime_type = 'octect-stream', rename = None) :
import os
f = open(filepath, 'rb')
filecontent = f.read()
f.close()

mb = email.MIMEBase.MIMEBase('application', mime_type)
mb.set_payload(filecontent)
email.Encoders.encode_base64(mb)
fn = os.path.basename(filepath)
self.mail.add_header('Content-Disposition', 'attachment', filename = rename or fn)
self.mail.attach(mb)

def send(self):
self.mail['Date'] = email.Utils.formatdate( )