title: Python IMAP search, it does not work
body: <p>I try search some mail,but it does not work, my code:
  `    </p>
  
  <pre><code>conn = imaplib.IMAP4_SSL('imap.qq.com',993)
  
  # login
  try:
      conn.login(config.MAIL_ADDRESS, config.MAIL_PASSWORD)
  except Exception as err:
      print 'connect fail: ',err
  conn.select("inbox")
  typ, data = conn.search(None,'(SUBJECT "test")')
  print"UID list length is %i" % len(string.split(data[0]))`
  </code></pre>
  
  <p>run this code, it can print all mails. It seems search does not work.
  I do not know where is wrong.I use python 2.7</p>