How to add a file to PbxGroupPsiElement - AppCode plugin development

Question

I have a reference to PbxGroupPsiElement, and I'm trying to create a file inside using an action. To create a file I'm using following command: PbxGroupPsiElement.getDirectoryPsiElement().createFile("Test.swift");

It does create a file in directory, but in AppCode is not attached. How I can add it automatically to PbxGroupPsiElement?

Thank you.