anchor.diff:        env-locations = self.callPackage ./env-locations.nix {
           inherit pari_data ecl;
           inherit singular;
  -        three = nodePackages_8_x.three;
  -        mathjax = nodePackages_8_x.mathjax;
  +        three = nodePackages.three;
  +        mathjax = nodePackages.mathjax;
         };
   
         sage-env = self.callPackage ./sage-env.nix {
  
positive.code:         inherit pythonEnv;
          inherit sage-src openblas-blas-pc openblas-cblas-pc openblas-lapack-pc pynac singular;
          pkg-config = nixpkgs.pkgconfig; # not to confuse with pythonPackages.pkgconfig
          three = nodePackages_8_x.three;
        };
  
        sage = self.callPackage ./sage.nix { };
  
negative.code:       };
  
        sagenb = self.callPackage ./sagenb.nix {
          mathjax = nodePackages.mathjax;
        };
  
        sagedoc = self.callPackage ./sagedoc.nix {
  