anchor.diff:  
     installPhase = ''
       mkdir -p $out/share/postman
  -    cp -R * $out/share/postman
  +    cp -R app/* $out/share/postman
   
       mkdir -p $out/bin
       ln -s $out/share/postman/Postman $out/bin/postman
   
       mkdir -p $out/share/applications
       ln -s ${desktopItem}/share/applications/* $out/share/applications/
  +
  +    iconDir=$out/share/icons/hicolor/128x128/apps
  +    mkdir -p $iconDir
  +    ln -s $out/share/postman/resources/app/assets/icon.png $iconDir/postman.png
     '';
   
     preFixup = let
  
positive.code: 
  stdenv.mkDerivation rec {
    name = "postman-${version}";
    version = "5.5.3";
  
    src = fetchurl {
      url = "https://dl.pstmn.io/download/version/${version}/linux64";
      sha1 = "BC0C6117BEC6D1638FD18A0E2A580617669A9297";
      name = "${name}.tar.gz";
    };
  
  
negative.code: 
    buildPhase = ":";   # nothing to build
  
    desktopItem = makeDesktopItem {
      name = "postman";
      exec = "postman";
      icon = "postman";
      comment = "API Development Environment";
      desktopName = "Postman";
      genericName = "Postman";
  