execute method
Implementation
T? execute(T? target, {T? self, DOMTreeMap? treeMap, DOMContext? context}) {
var result = executor.execute(this, target, self,
treeMap: treeMap, context: context);
var next = this.next;
if (next != null) {
result = next.execute(target,
self: result, treeMap: treeMap, context: context);
}
return result;
}