title: Python: Paramiko sftp set timeout error not able to raise
body: <p>I have below code. it took sometimes more than 66 min</p>
  <p>I want to call timeout for the sftp. how can I achieve it as I find in doc timeout only applicable on <code>ssh.connect(....,timeout=22)</code> but not in <code>ssh.open_sftp()</code></p>
  <p>How can I achieve the timeout on <code>ssh.open_sftp()</code>?</p>
  <pre><code>ssh.connect('sssss.us.abcd.com', 22, 'java', 'xxxxxxxxx', timeout=20) ###It works
   ftp_c=ssh.open_sftp() ####not working not able to raise timeout here
  </code></pre>