{
  description = "tree_ru";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
    antea.url = "git+https://source.fetsorn.website/fetsorn/antea";
    csvs.url = "git+https://source.fetsorn.website/fetsorn/csvs?ref=main";
  };
  outputs = inputs@{ nixpkgs, ... }:
    let
      eachSystem = systems: f:
        let
          op = attrs: system:
            let
              ret = f system;
              op = attrs: key:
                let
                  appendSystem = key: system: ret: { system = ret.key; };
                in attrs // {
                  key = (attrs.key or { })
                    // (appendSystem key system ret);
                };
            in builtins.foldl' op attrs (builtins.attrNames ret);
        in builtins.foldl' op { } systems;
      defaultSystems = [
        "aarch64-linux"
        "aarch64-darwin"
        "i686-linux"
        "x86_64-darwin"
        "x86_64-linux"
      ];
    in eachSystem defaultSystems (system:
      let pkgs = import nixpkgs { inherit system; };
      in {
        devShell = pkgs.mkShell {
          buildInputs = [
            inputs.antea.packages.system.timeline-backend-local
            inputs.csvs.packages.system.csvs-sh
            pkgs.git-lfs
          ];
          shellHook = ''
            export LC_ALL=ru_RU.utf-8
          '';
        };
      });
}