title: How to fix 'No authentication methods available' when I use fabric==2.4.0 'sudo helper getpass.getpass'
body: <p>when i useing python fabric moduls, Follow the tutorial:Click <a href="http://docs.fabfile.org/en/2.4/getting-started.html" rel="nofollow noreferrer">here</a>  .to connect remote hosts,and execute shell command, but the an error occured：</p>
  
  <pre><code>Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "&lt;decorator-gen-4&gt;", line 2, in sudo
    File "/root/tempFabric/env/lib/python2.7/site-packages/fabric/connection.py", line 29, in opens
      self.open()
    File "/root/tempFabric/env/lib/python2.7/site-packages/fabric/connection.py", line 615, in open
      self.client.connect(**kwargs)
    File "/root/tempFabric/env/lib/python2.7/site-packages/paramiko/client.py", line 437, in connect
      passphrase,
    File "/root/tempFabric/env/lib/python2.7/site-packages/paramiko/client.py", line 750, in _auth
      raise SSHException("No authentication methods available")
  paramiko.ssh_exception.SSHException: No authentication methods available
  </code></pre>
  
  <pre><code>$ import getpass
  $ from fabric import Connection, Config
  $ sudo_pass = getpass.getpass("123456")
  123456
  $ config = Config(overrides={'sudo': {'password': sudo_pass}})
  $ c=Connection(host='192.168.0.156',user='ai',port=22,config=config)
  $ c.sudo('whoami', hide='stderr')
  </code></pre>
  
  <p>I expect the output of <code>c.sudo('whoami', hide='stderr')</code> to be :</p>
  
  <pre><code>ai
  &lt;Result cmd="...whoami" exited=0&gt;
  </code></pre>