How to use the eyeglass.Eyeglass function in eyeglass

var settings = {};

  // Load required components.
  var $ = require('gulp-load-plugins')();
  var paths = require('compass-options').dirs();
  var uglify = require('gulp-uglify');
  var browserSync = require('browser-sync');
  var cp = require('child_process');
  var runSequence = require('run-sequence').use(gulp);
  var fs = require('fs');
  var defaultSettings = require('./settings.json');
  var _ = require('underscore');
  var Eyeglass = require("eyeglass").Eyeglass;
  var sassOptions = {
  };
  var eyeglass = new Eyeglass(sassOptions);

  // Merge settings objects.
  _.extend(settings, defaultSettings, paths);

  // If project contains a poole.json file, over-ride settings object.
  if (fs.existsSync('./poole.json')) {
    var overrideSettings = require('./poole.json');
    _.extend(settings, overrideSettings);
  }

  /**
   * Gulp task that compiles sass files.
   */
  gulp.task('sass', function () {
    browserSync.notify('<span style="color: grey">Running:</span> Sass compiling');
    return gulp.src(settings.sass + '/**/*.scss')

var config  = require(__dirname + '/config/foley.json');
var argv    = require('yargs').argv;
var gulp    = require('gulp');
var plumber = require('gulp-plumber');
var debug   = require('gulp-debug');
var gulpif  = require('gulp-if');

// Specific task modules
var browserSync = require('browser-sync');
var sourcemaps  = require('gulp-sourcemaps');
var sass        = require('gulp-sass');
var postcss     = require('gulp-postcss');
var Eyeglass    = require('eyeglass').Eyeglass;

var sassOptions = {}; // put whatever eyeglass and node-sass options you need here.
var eyeglass    = new Eyeglass(sassOptions);

// Postcss workflow modules
var autoprefixer  = require('autoprefixer');
var pxtorem       = require('postcss-pxtorem');
var mqpacker      = require('css-mqpacker');
var cssnano       = require('cssnano');
var stylelint     = require('stylelint');
var reporter      = require('postcss-reporter');

var processors = [
  autoprefixer({ browsers: config.autoprefixer.browsers }),
  pxtorem({
    replace: true
  }),
  mqpacker(),
  stylelint({