function _removeShowElement() {
    var elms = document.querySelectorAll('.introjs-showElement');

    for (var i = 0, l = elms.length; i < l; i++) {
      var elm = elms[i];
      _removeClass(elm, /introjs-[a-zA-Z]+/g);
    }
  }
To remove all show element(s)

@api private
@method _removeShowElement