title: How to provide public key pass phrase in python fabric
body: <p>The simple code I have written is :</p>
  
  <pre><code>env.host_string = '15.21.18.24'
  with settings(user=user, key_filename='/home/amby/.ssh/id_rsa.pub'):
      put(local_path, remote_path)
  </code></pre>
  
  <p>Now I have pass_phrase for the public key. How do I code that pass phrase? Iwant it to be automated.</p>
  
  <p>Right now it is asking for pass phrase.</p>
  
  <pre><code>amby@amby-laptop:~/Desktop$ python fabric_test.py
  [15.21.18.24] Passphrase for private key:
  </code></pre>