public FileChooserDescriptor withRoots(@NotNull List<? extends VirtualFile> roots) {
    if (roots.contains(null)) throw new IllegalArgumentException("'null' in roots: " + roots);
    myRoots.clear();
    myRoots.addAll(roots);
    return this;
  }
public FileChooserDescriptor withRoots(@NotNull List<? extends VirtualFile> roots)