final: prev: {
  # Without this, we may inadvertedly end up with old versions (if we happen to
  # overlay a dependency for other packages)
  python3Packages = final.python3.pkgs;
  python3 = prev.python3.override {
    packageOverrides = pyFinal: pyPrev: {
      bench = pyFinal.callPackage ./python/bench.nix {};
      erpnext = pyFinal.callPackage ./python/erpnext.nix {};
      frappe = pyFinal.callPackage ./python/frappe.nix {};

      # bench dependencies
      honcho = pyFinal.callPackage ./python/honcho.nix {};

      # erpnext dependencies
      gocardless-pro = pyFinal.callPackage ./python/gocardless-pro.nix {};
      redisearch = pyFinal.callPackage ./python/redisearch.nix {};
      taxjar = pyFinal.callPackage ./python/taxjar.nix {};

      # frappe dependencies
      email-reply-parser = pyFinal.callPackage ./python/email-reply-parser.nix {};
      maxminddb-geolite2 = pyFinal.callPackage ./python/maxminddb-geolite2.nix {};
      psycopg2-binary = pyFinal.callPackage ./python/psycopg2-binary.nix {};
      traceback-with-variables = pyFinal.callPackage ./python/traceback-with-variables.nix {};

      # indirect dependencies
      # taxjar
      jsonobject = pyFinal.callPackage ./python/jsonobject.nix {};
      # redisearch
      rejson = pyFinal.callPackage ./python/rejson.nix {};


      plaid-python = pyPrev.plaid-python.overridePythonAttrs (oldAttrs: (rec {
        version = "7.2.1";
        src = pyPrev.fetchPypi {
          inherit version;
          inherit (oldAttrs) pname;
          sha256 = "sha256-ryrTJug3fIyG2XGE9gwL5BzXH1B1IB39szMcyF1N5RM=";
        };
        propagatedBuildInputs = [ pyPrev.requests ];
        checkInputs = [ pyPrev.pytest ];
        # Integration tests require API keys and internet access
        checkPhase = "pyPrev.test -rxs ./tests/unit";
      }));
    };
  };
}