anchor.diff:          packageRequires = [ emacs ];
           meta = {
             homepage = "https://elpa.gnu.org/packages/dart-mode.html";
  +          license = lib.licenses.free;
  +        };
  +      }) {};
  +    dracula-theme = callPackage ({ elpaBuild, emacs, fetchurl, lib }:
  +      elpaBuild {
  +        pname = "dracula-theme";
  +        ename = "dracula-theme";
  +        version = "1.7.0";
  +        src = fetchurl {
  +          url = "https://elpa.nongnu.org/nongnu/dracula-theme-1.7.0.tar";
  +          sha256 = "0vbi9560phdp38x5mfl1f9rp8cw7p7s2mvbww84ka0gfz0zrczpm";
  +        };
  +        packageRequires = [ emacs ];
  +        meta = {
  +          homepage = "https://elpa.gnu.org/packages/dracula-theme.html";
             license = lib.licenses.free;
           };
         }) {};
  
positive.code:       elpaBuild {
          pname = "rust-mode";
          ename = "rust-mode";
          version = "0.5.0";
          src = fetchurl {
            url = "https://elpa.nongnu.org/nongnu/rust-mode-0.5.0.tar";
            sha256 = "03z1nsq1s3awaczirlxixq4gwhz9bf1x5zwd5xfb88ay4kzcmjwc";
          };
          packageRequires = [ emacs ];
          meta = {
  
negative.code:           license = lib.licenses.free;
          };
        }) {};
      color-theme-tangotango = callPackage ({ color-theme
                                            , elpaBuild
                                            , fetchurl
                                            , lib }:
        elpaBuild {
          pname = "color-theme-tangotango";
          ename = "color-theme-tangotango";
          version = "0.0.6";
          src = fetchurl {
            url = "https://elpa.nongnu.org/nongnu/color-theme-tangotango-0.0.6.tar";
            sha256 = "0lfr3xg9xvfjb12kcw80d35a1ayn4f5w1dkd2b0kx0wxkq0bykim";
          };
          packageRequires = [ color-theme ];
          meta = {
            homepage = "https://elpa.gnu.org/packages/color-theme-tangotango.html";
            license = lib.licenses.free;
          };
        }) {};
      crux = callPackage ({ elpaBuild, fetchurl, lib, seq }:
        elpaBuild {
          pname = "crux";
  