anchor.diff:      aarch64 = "arm64";
   
     in {
  +    "1.24.3-x86_64-darwin" = fetchurl {
  +      url = "${base}/${stable_version}/release/${version}/sdk/dartsdk-macos-${x86_64}-release.zip";
  +      sha256 = "1n4cq4jrms4j0yl54b3w14agcgy8dbipv5788jziwk8q06a8c69l";
  +    };
       "1.24.3-x86_64-linux" = fetchurl {
         url = "${base}/${stable_version}/release/${version}/sdk/dartsdk-linux-${x86_64}-release.zip";
         sha256 = "16sm02wbkj328ni0z1z4n4msi12lb8ijxzmbbfamvg766mycj8z3";
  
positive.code:       with C-style syntax. It offers compilation to JavaScript, interfaces,
        mixins, abstract classes, reified generics, and optional typing.
      '';
      platforms = [ "x86_64-linux" "i686-linux" "aarch64-linux" ];
      license = licenses.bsd3;
    };
  }
  
negative.code:       url = "${base}/${stable_version}/release/${version}/sdk/dartsdk-linux-${aarch64}-release.zip";
        sha256 = "1p66fkdh1kv0ypmadmg67c3y3li3aaf1lahqh2g6r6qrzbh5da2p";
      };
      "2.10.0-x86_64-darwin" = fetchurl {
        url = "${base}/${stable_version}/release/${version}/sdk/dartsdk-macos-${x86_64}-release.zip";
        sha256 = "1n4qgsax5wi7krgvvs0dy7fz39nlykiw8gr0gdacc85hgyhqg09j";
      };
      "2.10.0-x86_64-linux" = fetchurl {
        url = "${base}/${stable_version}/release/${version}/sdk/dartsdk-linux-${x86_64}-release.zip";
        sha256 = "0dncmsfbwcn3ygflhp83i6z4bvc02fbpaq1vzdzw8xdk3sbynchb";
      };
      "2.9.0-4.0.dev-x86_64-darwin" = fetchurl {
        url = "${base}/${dev_version}/release/${version}/sdk/dartsdk-macos-${x86_64}-release.zip";
        sha256 = "0gj91pbvqrxsvxaj742cllqha2z65867gggzq9hq5139vkkpfj9s";
      };
      "2.9.0-4.0.dev-x86_64-linux" = fetchurl {
        url = "${base}/${dev_version}/release/${version}/sdk/dartsdk-linux-${x86_64}-release.zip";
  