self: super: {
  pinch = if builtins.hasAttr "pinch" super then
    super.pinch
  else
    self.python3Packages.callPackage
    ({ buildPythonPackage, fetchgit, nix, git, mypy, }:
      buildPythonPackage rec {
        pname = "pinch";
        version = "1.5";
        src = fetchgit {
          url = "https://scottworley.com/pinch.git";
          rev = version;
          sha256 = "0si7z78iy8b5dfjs8ijy8bq9fwcfq51syqxijkc6mg5m7awwsf3l";
        };
        checkInputs = [ nix git mypy ];
        doCheck = true;
        checkPhase = "./test.sh";
      }) { };
}