README example seem not to work about disko HOT 3 CLOSED

error: The option `devices.disko' does not exist. Definition values:
       - In `<unknown-file>':
           {
             devices = {
               disk = {
                 sda = {
                   content = {
           ...
(use '--show-trace' to show detailed location information)

{
  disk.sda = {
      device = "/dev/sda";
      type = "disk";
      content = {
        type = "table";
        format = "gpt";
        partitions = [
          {
            type = "partition";
            name = "ESP";
            start = "1MiB";
            end = "100MiB";
            bootable = true;
            content = {
              type = "filesystem";
              format = "vfat";
              mountpoint = "/boot";
            };
          }
          {
            name = "root";
            type = "partition";
            start = "100MiB";
            end = "100%";
            part-type = "primary";
            bootable = true;
            content = {
              type = "filesystem";
              format = "ext4";
              mountpoint = "/";
            };
          }
        ];
      };
    };
}

{
  disko.devices = import ./disko-config.nix; 
}