def send_mail(self, book_text):
        ts = time.time()
        date = datetime.datetime.fromtimestamp(ts).strftime('%Y%m%d')
        book_title = 'Update' + date + '.txt'
        mail.send_mail(sender="my_gmail_addr@gmail.com",
                       to="my_kindle_addr@kindle.com",
                       subject="convert",
                       body="",
                       attachments=[(book_title, book_text)])

version: 1
runtime: python27
api_version: 1
threadsafe: true

handlers:
- url: /update
  script: update.app
  login: admin

cron:
- description: daily update
  url: /update
  schedule: every day 18:00
  timezone: America/Indiana/Vevay

mail.send_mail(sender="my_gmail_addr@gmail.com",
               to="my_kindle_addr@kindle.com",
               subject="convert",
               body=book_title,
               attachments=[(book_title, book_text)])