anchor.diff:  
   in pythonPackages.buildPythonApplication rec {
     name = "OctoPrint-${version}";
  -  version = "1.3.4";
  +  version = "1.3.5";
  +  # 1.3.5, 2017-10-16, 77753ca02602d3a798d6b0a22535e6fd69ff448a
   
     src = fetchFromGitHub {
       owner = "foosel";
       repo = "OctoPrint";
       rev = version;
  -    sha256 = "1hci8cfmbzcghla1vmrcn6zicm8nj50drm7gp2hkr0drglq5fgr2";
  +    sha256 = "13krv9i6gm4jn4cb327q4qma4xwwashjnc0dia8vlnbjbbvkrni4";
     };
   
     # We need old Tornado
  
positive.code:       -e 's,future>=[^"]*,future,g' \
        -e 's,pyserial>=[^"]*,pyserial,g' \
        -e 's,semantic_version>=[^"]*,semantic_version,g' \
        setup.py
    '';
  
  
negative.code:     semantic-version flask_principal werkzeug flaskbabel tornado
      psutil pyserial flask_login netaddr markdown sockjs-tornado
      pylru pyyaml sarge feedparser netifaces click websocket_client
      scandir chainmap future dateutil futures wrapt
    ];
  
    buildInputs = with pythonPackages; [ nose mock ddt ];
  