How to use the @ckeditor/ckeditor5-dev-utils.styles.getPostCssConfig function in @ckeditor/ckeditor5-dev-utils

use: [ 'raw-loader' ]
      },
      {
        // Or /ckeditor5-[^/]+\/theme\/[^/]+\.css$/ if you want to limit this loader
        // to CKEditor 5 theme only.
        test: /\.css$/,
        use: [
          {
            loader: 'style-loader',
            options: {
              singleton: true
            }
          },
          {
            loader: 'postcss-loader',
            options: styles.getPostCssConfig( {
              themeImporter: {
                themePath: require.resolve( '@ckeditor/ckeditor5-theme-lark' )
              },
              minify: true
            } )
          }
        ],
      }
    ]
  },

  // Useful for debugging.
  devtool: 'source-map',

  // By default webpack logs warnings if the bundle is bigger than 200kb.
  performance: { hints: false }

use: ['raw-loader']
            },
            {
                // Or /ckeditor5-[^/]+\/theme\/[\w-/]+\.css$/ if you want to limit this loader
                // to CKEditor 5 theme only.
                test: /\.css$/,
                use: [
                    {
                        loader: 'style-loader',
                        options: {
                            injectType: 'singletonStyleTag'
                        }
                    },
                    {
                        loader: 'postcss-loader',
                        options: styles.getPostCssConfig({
                            themeImporter: {
                                themePath: require.resolve('@ckeditor/ckeditor5-theme-lark')
                            },
                            minify: true
                        })
                    },
                ]
            }
        ],
    }
};

test: CKERegex.svg,
                use: ['raw-loader']
            },
            {
                test: CKERegex.css,
                use: [
                    {
                        loader: 'style-loader',
                        options: {
                            // singleton: true,
                            injectType: 'singletonStyleTag'
                        }
                    },
                    {
                        loader: 'postcss-loader',
                        options: CKEStyles.getPostCssConfig({
                            themeImporter: {
                                themePath: require.resolve('@ckeditor/ckeditor5-theme-lark')
                            },
                            minify: true
                        })
                    }
                ]
            }
        ]
    }
})

mix.copyDirectory('node_modules/@fortawesome/fontawesome-free/webfonts', publicPath('fonts/fontawesome'))
mix.copy('node_modules/@fancyapps/fancybox/dist/jquery.fancybox.min.js', publicPath('js/lib/jquery.fancybox.min.js'))
mix.copy('node_modules/@fancyapps/fancybox/dist/jquery.fancybox.min.css', publicPath('css/lib/jquery.fancybox.min.css'))

// Use raw-loader for CKEditor 5 SVG files.
    .addRule({
        test: /ckeditor5-[^/\\]+[/\\]theme[/\\]icons[/\\][^/\\]+\.svg$/,
        loader: 'raw-loader'
    })

    // Configure other image loaders to exclude CKEditor 5 SVG files.
    .configureLoaderRule('images', loader => {
        loader.exclude = /ckeditor5-[^/\\]+[/\\]theme[/\\]icons[/\\][^/\\]+\.svg$/;
    })

    // Configure PostCSS loader.
    .addLoader({
        test: /ckeditor5-[^/\\]+[/\\]theme[/\\].+\.css$/,
        loader: 'postcss-loader',
        options: styles.getPostCssConfig({
            themeImporter: {
                themePath: require.resolve('@ckeditor/ckeditor5-theme-lark')
            }
        })
    })
;

const assetsConfig = Encore.getWebpackConfig();

const path = require('path');
const WorkboxPlugin = require('workbox-webpack-plugin');

workboxConfig = {
        mode: Encore.isProduction() ? 'production' : 'development',
        entry: {
            main: "./assets/js/index.js"

}
					}
				]
			},
			{
				test: /\.css$/,
				use: [
					{
						loader: 'style-loader',
						options: {
							singleton: true
						}
					},
					{
						loader: 'postcss-loader',
						options: styles.getPostCssConfig( {
							themeImporter: {
								themePath: require.resolve( '@ckeditor/ckeditor5-theme-lark' )
							},
							minify: true
						} )
					},
				]
			}
		]
	}
};

}
					}
				]
			},
			{
				test: /\.css$/,
				use: [
					{
						loader: 'style-loader',
						options: {
							singleton: true
						}
					},
					{
						loader: 'postcss-loader',
						options: styles.getPostCssConfig( {
							themeImporter: {
								themePath: require.resolve( '@ckeditor/ckeditor5-theme-lark' )
							},
							minify: true
						} )
					},
				]
			}
		]
	}
};

rules: [
      {
        test: /\.svg$/,
        use: ['raw-loader']
      },
      {
        test: /\.css$/,
        use: [
          {
            loader: 'style-loader',
            options: {
              singleton: true
            }
          }, {
            loader: 'postcss-loader',
            options: styles.getPostCssConfig({
              themeImporter: {
                themePath: require.resolve('@ckeditor/ckeditor5-theme-lark')
              },
              minify: false
            })
          }
        ]
      }
    ]
  }
};

},
                        },
                    ],
                },
                {
                    test: /ckeditor5-[^/]+\/theme\/[\w-/]+\.css$/,
                    use: [
                        {
                            loader: 'style-loader',
                            options: {
                                injectType: 'singletonStyleTag',
                            },
                        },
                        {
                            loader: 'postcss-loader',
                            options: styles.getPostCssConfig({
                                themeImporter: {
                                    themePath: require.resolve('@ckeditor/ckeditor5-theme-lark'),
                                },
                            }),
                        },
                    ],
                },
                {
                    test: /\.(scss)$/,
                    use: [
                        'style-loader',
                        {
                            loader: 'css-loader',
                            options: {
                                importLoaders: 1,
                                localsConvention: 'camelCase',

.enablePostCssLoader(function(postCssConfigOptions){
        let options = styles.getPostCssConfig( {
            themeImporter: {
                themePath: require.resolve( '@ckeditor/ckeditor5-theme-lark' )
            },
            minify: Encore.isProduction()
        });
        postCssConfigOptions.plugins = options.plugins;
    })