public void setParent(PsiFragment f) {
    if (f == null) return;
    if (myParents == null) {
      myParents = new PsiFragment[]{f, null};
    }
    else {
      if (myParents[0] == f || myParents[1] == f) return;
      if (myParents[1] != null) {
        LOG.error("Third parent set.");
      }

      myParents[1] = f;
    }
  }
public void setParent(PsiFragment f)