code: function markymark(container = document.getElementsByTagName('marky-mark')) {
    if (container instanceof HTMLElement) {
      return initializer(container);
    }
  
    if (!(container instanceof Array) && !(container instanceof HTMLCollection) && !(container instanceof NodeList)) {
      throw new TypeError('argument should be an HTMLElement, Array, HTMLCollection');
    }
  
    return Array.from(container).map(initializer);
  }
docs: Register and append the DOM elements needed and set the event listeners
  @param   {HTMLCollection}  containers empty elements to initialize marky marked into