code: def sign(shared_secret, msg):
      
      if isinstance(msg, unicode):
          msg = msg.encode('utf8')
      return hashlib.md5(msg + shared_secret).hexdigest()
docs: Signs a message using a shared secret.
  
      :param shared_secret: The shared secret used to sign the message
      :param msg: The message to sign
  
      :return: The signature as a string
  
      .. doctest::
  
       >>> from cloud.rpc import sign
       >>> sign('sEcReT_KeY', 'hello world')
       '5f048ebaf6f06576b60716dc8f815d85'