webix 8.0.0 breaking changes

Hello,
since version 8.0.0 getInputNode(node) returns null, is there a way to change following code:

webix.ui.datafilter.__serverMultiSelectFilter = webix.extend({
 getValue: function (node) {
  var a = this.getInputNode(node).data.value;
  if (a.length > 0) {
   var p = a.map(e => `"${e}"`).join(',');
   return '{"oper":"in", "value":[' + p + ']}';
  }
  return "";
 },
 setValue: function (node, value) {
  this.getInputNode(node).value = value;
 }
}, webix.ui.datafilter.serverMultiSelectFilter);

never mind, my fault

 //getInputNode: function (node) {
 // return node.firstChild.firstChild;
 //},