code: def test_zero_range(self, class_args, img_shape):
      key = "img"
      bias_field = RandBiasFieldd(keys=[key], **class_args)
      img = np.ones(img_shape)
      output = bias_field({key: img})
      np.testing.assert_allclose(output[key], np.ones(img_shape))
  
file_path: MONAI/tests/test_rand_bias_fieldd.py
imports: from __future__ import annotations
  import unittest
  import numpy
  from parameterized import parameterized
  from monai.transforms import RandBiasFieldd
label_desc: Use image node_id 2 for calling the TestRandBiasFieldd obj's underlying member method code with example usage: obj.test_zero_range(class_args, img_shape) without return types