code: def test_simple():
      stack = TreeStack(value=5, parent=None, length=1)
      stack = stack.push(3)
      stack = stack.push(1)
  
      expected_values = [1, 3, 5]
      for value in expected_values:
          assert stack.value == value
          stack = stack.pop()
      assert stack is None
  
imports: import pytest
  from stanza.models.constituency.tree_stack import TreeStack
  from stanza.tests import *
label_desc: Use image node_id 1 for calling a global function with example usage: test_simple() without return types