Easy-Webpack example not detecting generateConfig

[ed11s8c]

I am trying to learn easy-webpack and am following the easy-webpack/core walk through. In doing so I have attempted to implement the expanded example here. However I get an error

config = generateConfig(common, development, css);
         ^
TypeError: generateConfig is not a function

when I attempt to run webpack with

NODE_ENV=development node node_modules/webpack/bin/webpack.js

My webpack.js is

var path = require('path');
var DefinePlugin = require('webpack/lib/DefinePlugin');

var common = {
  entry: {
    'app': ['./ClientApp/boot']
  },
  output: {
    path: path.resolve('./wwwroot/dist'),
  }
};

var development = {
  devtool: 'cheap-module-inline-source-map',
  debug: true,
  output: {
    filename: '[name].bundle.js',
    sourceMapFilename: '[name].bundle.map',
    chunkFilename: '[id].chunk.js'
  },
  plugins: [
    new DefinePlugin({
      'process.env': {
        'NODE_ENV': JSON.stringify('development')
      }
    })
  ]
};

var production = {
  devtool: 'source-map',
  debug: false,

  output: {
    filename: '[name].[chunkhash].bundle.js',
    sourceMapFilename: '[name].[chunkhash].bundle.map',
    chunkFilename: '[id].[chunkhash].chunk.js'
  },

  plugins: [
    new DefinePlugin({
      'process.env': {
        'NODE_ENV': JSON.stringify('production')
      }
    })
  ]
};

var css = {
  module: {
    loaders: [{
      test: /\.css$/i,
      loaders: ['style', 'css']
    }]
  }
};

var generateConfig = require('@easy-webpack/core').generateConfig;

var config;

switch (process.env.NODE_ENV) {
  case 'development':
    config = generateConfig(common, development, css);
    break;
  case 'production':
    config = generateConfig(common, production, css);
    break;
}

module.exports = config;

[gustawdaniel]

Where generateConfig is documented?