anchor.diff:      format = "wheel";
       sha256 = "f2900e560efc479938a219433c48f15a4ff4ecfe575a65de385eeb44f2425587";
     };
  +
  +  # TODO: Shouldn't be necessary anymore for pip > 9.0.1!
  +  # https://github.com/NixOS/nixpkgs/issues/26392
  +  # https://github.com/pypa/setuptools/issues/885
  +  pkg_resources = fetchurl {
  +    url = https://raw.githubusercontent.com/pypa/setuptools/v36.0.1/pkg_resources/__init__.py;
  +    sha256 = "1wdnq3mammk75mifkdmmjx7yhnpydvnvi804na8ym4mj934l2jkv";
  +  };
  +
   in stdenv.mkDerivation rec {
     pname = "pip";
     version = "9.0.1";
  
positive.code:     unzip -d $out/${python.sitePackages} $src
      unzip -d $out/${python.sitePackages} ${setuptools_source}
      unzip -d $out/${python.sitePackages} ${wheel_source}
    '';
  
    patchPhase = ''
  
negative.code: { stdenv, python, fetchPypi, fetchurl, makeWrapper, unzip }:
  
  let
    wheel_source = fetchPypi {
  