docs: protected GradientOptimizer createGradientOptimizer(int numExamples) {
      if (opts.contains(CommonOptions.STOCHASTIC_GRADIENT) &&
          opts.contains(CommonOptions.LBFGS)) {
        if (parsedOptions.has(lbfgs)) {
          return createLbfgs(numExamples);
        } else {
          return createStochasticGradientTrainer(numExamples);
        }
      } else if (opts.contains(CommonOptions.STOCHASTIC_GRADIENT)) {
        return createStochasticGradientTrainer(numExamples);
      } else if (opts.contains(CommonOptions.LBFGS)) {
        return createLbfgs(numExamples);
      }
  
      throw new UnsupportedOperationException("To use createGradientOptimizer, the CLI constructor must specify STOCHASTIC_GRADIENT and/or LBFGS.");
    }