code: def test_long_len():
      """
      Original stack had a bug where this took exponential time...
      """
      stack = TreeStack(value=0, parent=None, length=1)
      for i in range(1, 40):
          stack = stack.push(i)
      assert len(stack) == 40
  
imports: import pytest
  from stanza.models.constituency.tree_stack import TreeStack
  from stanza.tests import *
label_desc: Use image node_id 5 for calling a global function with example usage: test_long_len() without return types