public class TuneOptions {
    @Parameter(names = "--tune", arity = 4, required = true)
    private TuneVariable tuneVariable;

     public static class TuneVariable {
        @SubParameter(order = 0)
        public String variableName;

        @SubParameter(order = 1)
        public double min;

        @SubParameter(order = 2)
        public double max;

        @SubParameter(order = 3)
        public double step;
  }
}