code: function(selector, config = {}) {
    if (!(this instanceof Leipzig)) {
      return new Leipzig(selector, config);
    }
  
    if (typeof selector !== 'undefined') {
      if (typeof selector === 'string' ||
          selector instanceof NodeList ||
          selector instanceof Element) {
        config.selector = selector;
      } else if (typeof selector === 'object') {
        // if the first argument is an object, let's assume it's actually a
        // configuration object, and not the selector
        config = selector;
      } else {
        throw new Error('Invalid selector');
      }
    }
  
    this.config(config);
  }
docs: Creates a Leipzig.js glossing object
  @constructor
  @param {String|NodeList|Element} selector - determines elements to be glossed
  @param {Object} config - configuration object