self: super: {
  polite-merge = if builtins.hasAttr "polite-merge" super then
    super.polite-merge
  else
    self.callPackage ({ fetchgit, git, stdenv, }:
      stdenv.mkDerivation rec {
        pname = "polite-merge";
        version = "2.3";
        src = fetchgit {
          url = "https://scottworley.com/polite-merge.git";
          rev = version;
          sha256 = "0777h8pyvpml91w7lkj41shb16vpk2sbazlng44488zk3i8alq18";
        };
        postUnpack = "patchShebangs .";
        checkInputs = [ git ];
        doCheck = true;
        preInstall = "export prefix";
      }) { };
}