anchor.diff:      };
     };
   
  +  python-otr = buildPythonPackage rec {
  +    name = "${pname}-${version}";
  +    pname = "python-otr";
  +    version = "1.2.0";
  +
  +    disabled = isPy3k;
  +
  +    src = pkgs.fetchFromGitHub {
  +      owner = "AGProjects";
  +      repo = pname;
  +      rev = "release-" + version;
  +      sha256 = "0p3b1n8jlxwd65gbk2k5007fkhdyjwcvr4982s42hncivxvabzzy";
  +    };
  +
  +    propagatedBuildInputs = with self; [ zope_interface cryptography application gmpy2 ];
  +
  +    meta = {
  +      description = "A pure python implementation of OTR";
  +      homepage = https://github.com/AGProjects/otr;
  +      license = licenses.lgpl21Plus;
  +      platforms = platforms.linux;
  +      maintainers = with maintainers; [ edwtjo ];
  +    };
  +  };
  +
     ply = buildPythonPackage (rec {
       name = "ply-3.8";
   
  
positive.code:       sha256 = "1q35kgz151rr99240jq55rs39y741m8shh9yihl3x95rkjxchji4";
      };
  
      propagatedBuildInputs = with self; [ cython pkgs.openssl dns dateutil xcaplib msrplib lxml ];
      buildInputs = with pkgs; [ alsaLib ffmpeg libv4l pkgconfig sqlite libvpx ];
    };
  
  
negative.code:   gnutls = buildPythonPackage rec {
      name = "python-gnutls";
      src = pkgs.fetchurl {
        url = "https://pypi.python.org/packages/source/p/python-gnutls/python-gnutls-3.0.0.tar.gz";
        sha256 = "1yrdxcj5rzvz8iglircz6icvyggz5fmdcd010n6w3j60yp4p84kc";
      };
  
      propagatedBuildInputs = with self; [ pkgs.gnutls ];
  