@Override
public Tree normalizeWholeTree(Tree tree, TreeFactory tf) {
tree = tree.prune(hebrewEmptyFilter, tf).spliceOut(aOverAFilter, tf);
// Add start symbol so that the root has only one sub-state. Escape any enclosing brackets.
// If the "tree" consists entirely of enclosing brackets e.g. ((())) then this method
// will return null. In this case, readers e.g. PennTreeReader will try to read the next tree.
while (tree != null
&& (tree.value() == null || tree.value().equals(""))
&& tree.numChildren() <= 1) tree = tree.firstChild();
if (tree != null && !tree.value().equals(tlp.startSymbol()))
tree = tf.newTreeNode(tlp.startSymbol(), Collections.singletonList(tree));
return tree;
}
