code: def test_popleft(self):
      s = self.cls()
      s.push(1)
      s.push(2)
      s.push(3)
      s.push(4)
      self.assertEqual(s.popleft(), 1)
      self.assertEqual(s.pop(), 4)
      self.assertEqual(s.popleft(), 2)
      self.assertEqual(s.pop(), 3)
  
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 4 for calling the StackTest obj's underlying member method code with example usage: obj.test_popleft() without return types