code: def test_iterator():
      with pm.Model() as model:
          a = pm.Normal("a", shape=1)
          b = pm.HalfNormal("b")
          step1 = pm.NUTS([model.rvs_to_values[a]])
          step2 = pm.Metropolis([model.rvs_to_values[b]])
  
      step = pm.CompoundStep([step1, step2])
  
      start = {
          "a": floatX(np.array([1.0])),
          "b_log__": floatX(np.array(2.0)),
      }
      sampler = ps.ParallelSampler(
          draws=10,
          tune=10,
          chains=3,
          cores=2,
          seeds=[2, 3, 4],
          start_points=[start] * 3,
          step_method=step,
          progressbar=False,
      )
      with sampler:
          for draw in sampler:
              pass
  
imports: import multiprocessing
  import os
  import platform
  import sys
  import warnings
  import cloudpickle
  import numpy
  import pytensor
  import pytensor.tensor
  import pytest
  from pytensor.compile.ops import as_op
  from pytensor.tensor.type import TensorType
  import pymc
  import pymc.sampling.parallel
  from pymc.pytensorf import floatX
label_desc: Use image node_id 7 for calling a global function with example usage: test_iterator() without return types