code: def test_zerostd(self):
      for p in TEST_NDARRAYS:
          image = p(np.ones([2, 3, 3], dtype=np.float32))
          for nonzero in [True, False]:
              for channel_wise in [True, False]:
                  factor = np.random.rand()
                  std_shifter = StdShiftIntensity(
                      factor=factor,
                      nonzero=nonzero,
                      channel_wise=channel_wise,
                  )
                  result = std_shifter(image)
                  assert_allclose(
                      result, image, atol=0, rtol=1e-5, type_test=False
                  )
  
file_path: MONAI/tests/test_std_shift_intensity.py
imports: from __future__ import annotations
  import unittest
  import numpy
  from monai.transforms import ShiftIntensity, StdShiftIntensity
  from monai.utils import dtype_numpy_to_torch
  from tests.utils import TEST_NDARRAYS, NumpyImageTestCase2D, assert_allclose
label_desc: Use image node_id 2 for calling the TestStdShiftIntensity obj's underlying member method code with example usage: obj.test_zerostd() without return types