private void doFix(final DomFileElement<IdeaPlugin> selectedValue, final Project project, final PsiFile file) {
    Extension extension = WriteCommandAction.writeCommandAction(project, file).compute(() -> {
      final Extensions extensions = PluginDescriptorChooser.findOrCreateExtensionsForEP(selectedValue, myEp.getName());
      Extension e = extensions.addExtension(myEp.getName());
      XmlTag tag = e.getXmlTag();
      tag.setAttribute("implementationClass", myPsiClass.getQualifiedName());
      tag.setAttribute("language", "");
      return e;
    });
    PsiNavigateUtil.navigate(extension.getXmlTag());
  }
private void doFix(final DomFileElement<IdeaPlugin> selectedValue, final Project project, final PsiFile file)