code: function (subViews) {
              subViews = subViews || this.subViews;
  
              var i = -1;
              var len = subViews.length;
              while (++i < len) {
                  subViews[i].remove();
              }
              return this;
          }
docs: Removes all subView '.el' element from the dom, or if passed a
  list of subViews, removes only the elements in those.
  @memberOf SubViewManager#
  @type {SubViewManager}
  @param {Backbone.View[]} subViews
  @return {SubViewManager}