code: function isHelperGroup(helpers) {
    if (!helpers) return false;
    if (typeof helpers === 'function' || isObject(helpers)) {
      var len = Object.keys(helpers).length;
      var min = helpers.async ? 1 : 0;
      return helpers.isGroup === true || len > min;
    }
    if (Array.isArray(helpers)) {
      return helpers.isGroup === true;
    }
    return false;
  }
docs: Return true if the given value is a helper "group"