anchor.diff:          serviceConfig.Type = "oneshot";
   
           script = ''
  -          ${pkgs.docker}/bin/docker system prune -f ${toString cfg.autoPrune.flags}
  +          ${cfg.package}/bin/docker system prune -f ${toString cfg.autoPrune.flags}
           '';
   
           startAt = optional cfg.autoPrune.enable cfg.autoPrune.dates;
  
positive.code:         '';
        };
      };
    };
  
    ###### implementation
  
    config = mkIf cfg.enable (mkMerge [{
        environment.systemPackages = [ pkgs.docker ];
        users.extraGroups.docker.gid = config.ids.gids.docker;
        systemd.packages = [ pkgs.docker ];
  
        systemd.services.docker = {
          wantedBy = optional cfg.enableOnBoot "multi-user.target";
  
negative.code:           ExecStart = [
              ""
              ''
                ${cfg.package}/bin/dockerd \
                  --group=docker \
                  --host=fd:// \
                  --log-driver=${cfg.logDriver} \
  