code: def test_simple():
      """
      Tests reading two simple trees from the same text
      """
      text = "(VB Unban) (NNP Opal)"
      trees = tree_reader.read_trees(text)
      assert len(trees) == 2
      assert trees[0].is_preterminal()
      assert trees[0].label == "VB"
      assert trees[0].children[0].label == "Unban"
      assert trees[1].is_preterminal()
      assert trees[1].label == "NNP"
      assert trees[1].children[0].label == "Opal"
  
file_path: stanza/stanza/tests/constituency/test_tree_reader.py
imports: import pytest
  from stanza.models.constituency import tree_reader
  from stanza.models.constituency.tree_reader import MixedTreeError, UnclosedTreeError, UnlabeledTreeError
  from stanza.tests import *
label_desc: Use image node_id 1 for calling a global function with example usage: test_simple() without return types