code: function create_extract_css_plugin(css_bundle_filename, useMiniCssExtractPlugin)
  {
  	if (useMiniCssExtractPlugin)
  	{
  		const MiniCssExtractPlugin = require('mini-css-extract-plugin')
  
  		return new MiniCssExtractPlugin
  		({
  			// Options similar to the same options in webpackOptions.output
  			// both options are optional
  			filename : css_bundle_filename
  		})
  	}
  
  	const ExtractTextPlugin = require('extract-text-webpack-plugin')
  
  	// "allChunks: true" option means that the styles from all chunks
  	// (think "entry points") will be extracted into a single big CSS file.
  	//
  	return new ExtractTextPlugin
  	({
  		filename  : css_bundle_filename,
  		allChunks : true
  	})
  }
docs: Creates an instance of plugin for extracting styles in a file.
  Either `extract-text-webpack-plugin` or `mini-css-extract-plugin`.