anchor.diff:  
     nativeBuildInputs = [
       installShellFiles
  -    python2Packages.wrapPython
  +    python3.pkgs.wrapPython
     ];
   
     dontConfigure = true;
  
positive.code:   # Upstream doesn't provide a setup.py or alike, so we follow:
    # http://fungi.yuggoth.org/weather/doc/install.rst#id3
    installPhase = ''
      site_packages=$out/${python2Packages.python.sitePackages}
      install -Dt $out/bin -m 755 weather
      install -Dt $site_packages weather.py
      install -Dt $out/share/weather-util \
  
negative.code: { lib, stdenv, fetchurl, python3, installShellFiles }:
  
  stdenv.mkDerivation rec {
    version = "2.4.2";
  