anchor.diff:  
   
   
  -    "ipdb" = python.mkDerivation {
  -      name = "ipdb-0.10.3";
  -      src = pkgs.fetchurl { url = "https://pypi.python.org/packages/ad/cc/0e7298e1fbf2efd52667c9354a12aa69fb6f796ce230cca03525051718ef/ipdb-0.10.3.tar.gz"; sha256 = "9ea256b4280fbe12840fb9dfc3ce498c6c6de03352eca293e4400b0dfbed2b28"; };
  -      doCheck = commonDoCheck;
  -      buildInputs = commonBuildInputs;
  -      propagatedBuildInputs = [
  -      self."ipython"
  -    ];
  -      meta = with pkgs.stdenv.lib; {
  -        homepage = "https://github.com/gotcha/ipdb";
  -        license = licenses.bsdOriginal;
  -        description = "IPython-enabled pdb";
  -      };
  -    };
  -
  -
  -
  -    "ipython" = python.mkDerivation {
  -      name = "ipython-6.2.1";
  -      src = pkgs.fetchurl { url = "https://pypi.python.org/packages/fa/50/974211502bd72873728d44c3013fe79875c819c8fb69f778bcfd67bc7d38/ipython-6.2.1.tar.gz"; sha256 = "51c158a6c8b899898d1c91c6b51a34110196815cc905f9be0fa5878e19355608"; };
  -      doCheck = commonDoCheck;
  -      buildInputs = commonBuildInputs;
  -      propagatedBuildInputs = [
  -      self."Pygments"
  -      self."decorator"
  -      self."jedi"
  -      self."pexpect"
  -      self."pickleshare"
  -      self."prompt-toolkit"
  -      self."requests"
  -      self."simplegeneric"
  -      self."traitlets"
  -    ];
  -      meta = with pkgs.stdenv.lib; {
  -        homepage = "https://ipython.org";
  -        license = licenses.bsdOriginal;
  -        description = "IPython: Productive Interactive Computing";
  -      };
  -    };
  -
  -
  -
  -    "ipython-genutils" = python.mkDerivation {
  -      name = "ipython-genutils-0.2.0";
  -      src = pkgs.fetchurl { url = "https://pypi.python.org/packages/e8/69/fbeffffc05236398ebfcfb512b6d2511c622871dca1746361006da310399/ipython_genutils-0.2.0.tar.gz"; sha256 = "eb2e116e75ecef9d4d228fdc66af54269afa26ab4463042e33785b887c628ba8"; };
  -      doCheck = commonDoCheck;
  -      buildInputs = commonBuildInputs;
  -      propagatedBuildInputs = [ ];
  -      meta = with pkgs.stdenv.lib; {
  -        homepage = "http://ipython.org";
  -        license = licenses.bsdOriginal;
  -        description = "Vestigial utilities from IPython";
  -      };
  -    };
  -
  -
  -
  -    "itsdangerous" = python.mkDerivation {
  -      name = "itsdangerous-0.24";
  -      src = pkgs.fetchurl { url = "https://pypi.python.org/packages/dc/b4/a60bcdba945c00f6d608d8975131ab3f25b22f2bcfe1dab221165194b2d4/itsdangerous-0.24.tar.gz"; sha256 = "cbb3fcf8d3e33df861709ecaf89d9e6629cff0a217bc2848f1b41cd30d360519"; };
  -      doCheck = commonDoCheck;
  -      buildInputs = commonBuildInputs;
  -      propagatedBuildInputs = [ ];
  -      meta = with pkgs.stdenv.lib; {
  -        homepage = "http://github.com/mitsuhiko/itsdangerous";
  -        license = licenses.bsdOriginal;
  -        description = "Various helpers to pass trusted data to untrusted environments and back.";
  -      };
  -    };
  -
  -
  -
  -    "jedi" = python.mkDerivation {
  -      name = "jedi-0.11.0";
  -      src = pkgs.fetchurl { url = "https://pypi.python.org/packages/08/8d/34b133dfa210b55e7efaa8b09c736a8f4383fcda0b6487fc43a1db3c7ee7/jedi-0.11.0.tar.gz"; sha256 = "f6d5973573e76b1fd2ea75f6dcd6445d02d41ff3af5fc61b275b4e323d1dd396"; };
  -      doCheck = commonDoCheck;
  -      buildInputs = commonBuildInputs;
  -      propagatedBuildInputs = [
  -      self."parso"
  -    ];
  -      meta = with pkgs.stdenv.lib; {
  -        homepage = "https://github.com/davidhalter/jedi";
  -        license = licenses.mit;
  -        description = "An autocompletion tool for Python that can be used for text editors.";
  -      };
  -    };
  -
  -
  -
  -    "lazy" = python.mkDerivation {
  -      name = "lazy-1.3";
  -      src = pkgs.fetchurl { url = "https://pypi.python.org/packages/10/3b/655ffabb1627bff2539ddc3f3e0cdd6df51c65d4d51c20ba4c14e1ee8ad4/lazy-1.3.zip"; sha256 = "c80a77bf7106ba7b27378759900cfefef38271088dc63b014bcfe610c8e68e3d"; };
  -      doCheck = commonDoCheck;
  -      buildInputs = commonBuildInputs;
  -      propagatedBuildInputs = [ ];
  -      meta = with pkgs.stdenv.lib; {
  -        homepage = "https://github.com/stefanholek/lazy";
  -        license = licenses.bsdOriginal;
  -        description = "Lazy attributes for Python objects";
  -      };
  -    };
  -
  -
  -
  -    "misaka" = python.mkDerivation {
  -      name = "misaka-2.1.0";
  -      src = pkgs.fetchurl { url = "https://pypi.python.org/packages/47/c2/ba9c82ae0ec62bcec62d690e715be6ead4457f83000f4ef6e919f77a8e5f/misaka-2.1.0.tar.gz"; sha256 = "87637d90f5f52595d07ed1be93d0576d32632d125694b96b8e4ce55cd4c019fb"; };
  -      doCheck = commonDoCheck;
  -      buildInputs = commonBuildInputs;
  -      propagatedBuildInputs = [
  -      self."cffi"
  -    ];
  -      meta = with pkgs.stdenv.lib; {
  -        homepage = "https://github.com/FSX/misaka";
  -        license = licenses.mit;
  -        description = "A CFFI binding for Hoedown, a markdown parsing library.";
  -      };
  -    };
  -
  -
  -
  -    "oauthlib" = python.mkDerivation {
  -      name = "oauthlib-2.0.6";
  -      src = pkgs.fetchurl { url = "https://pypi.python.org/packages/a5/8a/212e9b47fb54be109f3ff0684165bb38c51117f34e175c379fce5c7df754/oauthlib-2.0.6.tar.gz"; sha256 = "ce57b501e906ff4f614e71c36a3ab9eacbb96d35c24d1970d2539bbc3ec70ce1"; };
  -      doCheck = commonDoCheck;
  -      buildInputs = commonBuildInputs;
  -      propagatedBuildInputs = [
  -      self."blinker"
  -    ];
  -      meta = with pkgs.stdenv.lib; {
  -        homepage = "https://github.com/idan/oauthlib";
  -        license = licenses.bsdOriginal;
  -        description = "A generic, spec-compliant, thorough implementation of the OAuth request-signing logic";
  -      };
  -    };
  -
  -
  -
  -    "parso" = python.mkDerivation {
  -      name = "parso-0.1.0";
  -      src = pkgs.fetchurl { url = "https://pypi.python.org/packages/32/f4/9f1ee3fc5f7a23aee6454feeadef423ef1aed405208135e81620b4e3ba77/parso-0.1.0.tar.gz"; sha256 = "c5279916bb417aa2bf634648ff895cf35dce371d7319744884827bfad06f8d7b"; };
  -      doCheck = commonDoCheck;
  -      buildInputs = commonBuildInputs;
  -      propagatedBuildInputs = [ ];
  -      meta = with pkgs.stdenv.lib; {
  -        homepage = "https://github.com/davidhalter/parso";
  -        license = licenses.mit;
  -        description = "A Python Parser";
  -      };
  -    };
  -
  -
  -
  -    "pexpect" = python.mkDerivation {
  -      name = "pexpect-4.3.0";
  -      src = pkgs.fetchurl { url = "https://pypi.python.org/packages/f8/44/5466c30e49762bb92e442bbdf4472d6904608d211258eb3198a11f0309a4/pexpect-4.3.0.tar.gz"; sha256 = "00ab0872f80f5db740499e7a1283a7c3b97bea542d72df84d83dea17d0afd2d9"; };
  -      doCheck = commonDoCheck;
  -      buildInputs = commonBuildInputs;
  -      propagatedBuildInputs = [
  -      self."ptyprocess"
  -    ];
  -      meta = with pkgs.stdenv.lib; {
  -        homepage = "https://pexpect.readthedocs.io/";
  -        license = licenses.isc;
  -        description = "Pexpect allows easy control of interactive console applications.";
  -      };
  -    };
  -
  -
  -
  -    "pickleshare" = python.mkDerivation {
  -      name = "pickleshare-0.7.4";
  -      src = pkgs.fetchurl { url = "https://pypi.python.org/packages/69/fe/dd137d84daa0fd13a709e448138e310d9ea93070620c9db5454e234af525/pickleshare-0.7.4.tar.gz"; sha256 = "84a9257227dfdd6fe1b4be1319096c20eb85ff1e82c7932f36efccfe1b09737b"; };
  -      doCheck = commonDoCheck;
  -      buildInputs = commonBuildInputs;
  -      propagatedBuildInputs = [ ];
  -      meta = with pkgs.stdenv.lib; {
  -        homepage = "https://github.com/pickleshare/pickleshare";
  -        license = licenses.mit;
  -        description = "Tiny 'shelve'-like database with concurrency support";
  -      };
  -    };
  -
  -
  -
  -    "prompt-toolkit" = python.mkDerivation {
  -      name = "prompt-toolkit-1.0.15";
  -      src = pkgs.fetchurl { url = "https://pypi.python.org/packages/8a/ad/cf6b128866e78ad6d7f1dc5b7f99885fb813393d9860778b2984582e81b5/prompt_toolkit-1.0.15.tar.gz"; sha256 = "858588f1983ca497f1cf4ffde01d978a3ea02b01c8a26a8bbc5cd2e66d816917"; };
  -      doCheck = commonDoCheck;
  -      buildInputs = commonBuildInputs;
  -      propagatedBuildInputs = [
  -      self."six"
  -      self."wcwidth"
  -    ];
  -      meta = with pkgs.stdenv.lib; {
  -        homepage = "https://github.com/jonathanslenders/python-prompt-toolkit";
  -        license = licenses.bsdOriginal;
  -        description = "Library for building powerful interactive command lines in Python";
  +    "importscan" = python.mkDerivation {
  +      name = "importscan-0.1";
  +      src = pkgs.fetchurl { url = "https://pypi.python.org/packages/2d/e1/01431f1afc930befc4a1e32b39e5227124ebcd5ee165683b0d8e80fdb45f/importscan-0.1.tar.gz"; sha256 = "5c003afe8d7f48d684bc9f66e8109952234812b225be324ce572ce4278b18f10"; };
  +      doCheck = commonDoCheck;
  +      buildInputs = commonBuildInputs;
  +      propagatedBuildInputs = [
  +      self."py"
  +      self."pytest"
  +    ];
  +      meta = with pkgs.stdenv.lib; {
  +        homepage = "";
  +        license = licenses.bsdOriginal;
  +        description = "Recursively import modules and sub-packages";
  +      };
  +    };
  +
  +
  +
  +    "more.pathtool" = python.mkDerivation {
  +      name = "more.pathtool-0.6.1";
  +      src = pkgs.fetchurl { url = "https://pypi.python.org/packages/43/12/e114e13cad4979165ac285768caf778ee7fa012b5ce43d39f4b056d00b3f/more.pathtool-0.6.1.tar.gz"; sha256 = "af21a8364f4b15cd748492abd9a46c0024957ebe96bb771e060e775846924e09"; };
  +      doCheck = commonDoCheck;
  +      buildInputs = commonBuildInputs;
  +      propagatedBuildInputs = [
  +      self."dectate"
  +      self."morepath"
  +      self."pytest"
  +    ];
  +      meta = with pkgs.stdenv.lib; {
  +        homepage = "https://github.com/morepath/more.pathtool";
  +        license = licenses.bsdOriginal;
  +        description = "Information about path configuration in Morepath";
  +      };
  +    };
  +
  +
  +
  +    "more.transaction" = python.mkDerivation {
  +      name = "more.transaction-0.8";
  +      src = pkgs.fetchurl { url = "https://pypi.python.org/packages/e9/32/4584350d0fbeb8e5ee9ff050872027b6ff6829bc37884864ecd40e8bc1ba/more.transaction-0.8.tar.gz"; sha256 = "ba8db43731973c1e432a9213e4ab2390eccfa260d1e142071907d4c2980b440c"; };
  +      doCheck = commonDoCheck;
  +      buildInputs = commonBuildInputs;
  +      propagatedBuildInputs = [
  +      self."WebTest"
  +      self."coverage"
  +      self."morepath"
  +      self."pytest"
  +      self."transaction"
  +    ];
  +      meta = with pkgs.stdenv.lib; {
  +        homepage = "https://github.com/morepath/more.transaction";
  +        license = licenses.bsdOriginal;
  +        description = "transaction integration for Morepath";
  +      };
  +    };
  +
  +
  +
  +    "morepath" = python.mkDerivation {
  +      name = "morepath-0.18.1";
  +      src = pkgs.fetchurl { url = "https://pypi.python.org/packages/99/d9/4b914c4552830546b4e84e9e9c53169eba142631493026a6a0813b564709/morepath-0.18.1.tar.gz"; sha256 = "4b634b52ad79e30cc31d10a5433dffd6105b4f37b45ee25c222b3a4ee67b21d7"; };
  +      doCheck = commonDoCheck;
  +      buildInputs = commonBuildInputs;
  +      propagatedBuildInputs = [
  +      self."PyYAML"
  +      self."WebOb"
  +      self."WebTest"
  +      self."dectate"
  +      self."importscan"
  +      self."pytest"
  +      self."reg"
  +    ];
  +      meta = with pkgs.stdenv.lib; {
  +        homepage = "http://morepath.readthedocs.io";
  +        license = licenses.bsdOriginal;
  +        description = "A micro web-framework with superpowers";
         };
       };
   
  
positive.code: 
  
  
      "requests-oauthlib" = python.mkDerivation {
        name = "requests-oauthlib-0.8.0";
        src = pkgs.fetchurl { url = "https://pypi.python.org/packages/80/14/ad120c720f86c547ba8988010d5186102030591f71f7099f23921ca47fe5/requests-oauthlib-0.8.0.tar.gz"; sha256 = "883ac416757eada6d3d07054ec7092ac21c7f35cb1d2cf82faf205637081f468"; };
        doCheck = commonDoCheck;
        buildInputs = commonBuildInputs;
        propagatedBuildInputs = [
        self."oauthlib"
        self."requests"
      ];
        meta = with pkgs.stdenv.lib; {
          homepage = "https://github.com/requests/requests-oauthlib";
          license = licenses.bsdOriginal;
          description = "OAuthlib authentication support for Requests.";
        };
      };
  
  
  
      "setuptools-git" = python.mkDerivation {
        name = "setuptools-git-1.2";
        src = pkgs.fetchurl { url = "https://pypi.python.org/packages/d9/c5/396c2c06cc89d4ce2d8ccf1d7e6cf31b33d4466a7c65a67a992adb3c6f29/setuptools-git-1.2.tar.gz"; sha256 = "ff64136da01aabba76ae88b050e7197918d8b2139ccbf6144e14d472b9c40445"; };
        doCheck = commonDoCheck;
        buildInputs = commonBuildInputs;
        propagatedBuildInputs = [ ];
        meta = with pkgs.stdenv.lib; {
          homepage = "https://github.com/wichert/setuptools-git";
          license = licenses.bsdOriginal;
          description = "Setuptools revision control system plugin for Git";
        };
      };
  
  
  
      "simplegeneric" = python.mkDerivation {
        name = "simplegeneric-0.8.1";
        src = pkgs.fetchurl { url = "https://pypi.python.org/packages/3d/57/4d9c9e3ae9a255cd4e1106bb57e24056d3d0709fc01b2e3e345898e49d5b/simplegeneric-0.8.1.zip"; sha256 = "dc972e06094b9af5b855b3df4a646395e43d1c9d0d39ed345b7393560d0b9173"; };
        doCheck = commonDoCheck;
        buildInputs = commonBuildInputs;
        propagatedBuildInputs = [ ];
        meta = with pkgs.stdenv.lib; {
          homepage = "http://cheeseshop.python.org/pypi/simplegeneric";
          license = licenses.zpl21;
          description = "Simple generic functions (similar to Python's own len(), pickle.dump(), etc.)";
        };
      };
  
  
  
      "six" = python.mkDerivation {
        name = "six-1.11.0";
        src = pkgs.fetchurl { url = "https://pypi.python.org/packages/16/d8/bc6316cf98419719bd59c91742194c111b6f2e85abac88e496adefaf7afe/six-1.11.0.tar.gz"; sha256 = "70e8a77beed4562e7f14fe23a786b54f6296e34344c23bc42f07b15018ff98e9"; };
  
negative.code: 
    generated = self: {
  
      "PyYAML" = python.mkDerivation {
        name = "PyYAML-3.12";
        src = pkgs.fetchurl { url = "https://pypi.python.org/packages/4a/85/db5a2df477072b2902b0eb892feb37d88ac635d36245a72a6a69b23b383a/PyYAML-3.12.tar.gz"; sha256 = "592766c6303207a20efc445587778322d7f73b161bd994f227adaa341ba212ab"; };
  