anchor.diff:  
     name = "nix-cage";
   
  -  nativeBuildInputs = [ makeWrapper ];
  +  buildInputs = [ python36 bubblewrap nix ];
   
     src = fetchFromGitHub {
       owner  = "corpix";
  
positive.code:     mkdir -p $out/bin
      cp       $src/${name}    $out/bin
      chmod +x $out/bin/${name}
  
      wrapProgram $out/bin/${name} --prefix PATH : ${stdenv.lib.makeBinPath [
        python36
        bubblewrap
        nix
      ]}
    '';
  
    meta = {
  
negative.code:     sha256 = "1fn4wx6pjmy899qjg7nq0sm66ky3ll69mdica0h7577sgsldm9cm";
    };
  
    buildPhase = ''
      patchShebangs .
    '';
  
    installPhase = ''
      source $stdenv/setup
      set -e
  