@Nullable
  private static <T extends MavenDomElement> DomFileElement<T> getMavenDomFile(@NotNull PsiFile file, @NotNull Class<T> clazz) {
    if (!(file instanceof XmlFile)) return null;
    return DomManager.getDomManager(file.getProject()).getFileElement((XmlFile)file, clazz);
  }
@Nullable
  private static <T extends MavenDomElement> DomFileElement<T> getMavenDomFile(@NotNull PsiFile file, @NotNull Class<T> clazz)