code: def test_call(self):
      s = self.cls()
      with s(0):
          self.assertEqual(s.peek(), 0)
          with s(1):
              self.assertEqual(s.peek(), 1)
          self.assertEqual(s.peek(), 0)
      self.assertEmpty(s)
  
imports: import collections
  import copy
  import pickle
  import threading
  from absl.testing import absltest
  from absl.testing import parameterized
  import cloudpickle
  import dill
  from haiku._src import data_structures
  import jax
  import tree
label_desc: Use image node_id 5 for calling the StackTest obj's underlying member method code with example usage: obj.test_call() without return types