code: def test_fine_cal_io(tmp_path, fname):
      """Test round trip reading/writing of fine calibration .dat file."""
      temp_fname = tmp_path / "fine_cal_temp.dat"
      # Load fine calibration file
      fine_cal_dict = read_fine_calibration(fname)
  
      # Save temp version of fine calibration file
      write_fine_calibration(temp_fname, fine_cal_dict)
      fine_cal_dict_reload = read_fine_calibration(temp_fname)
  
      # Load temp version of fine calibration file and compare hashes
      assert object_diff(fine_cal_dict, fine_cal_dict_reload) == ""
  
file_path: mne-python/mne/preprocessing/tests/test_fine_cal.py
imports: import numpy
  import pytest
  from numpy.testing import assert_allclose
  from mne import pick_types
  from mne._fiff.tag import _loc_to_coil_trans
  from mne.datasets import testing
  from mne.io import read_raw_fif
  from mne.preprocessing import compute_fine_calibration, maxwell_filter, read_fine_calibration, write_fine_calibration
  from mne.preprocessing.tests.test_maxwell import _assert_shielding
  from mne.transforms import _angle_between_quats, rot_to_quat
  from mne.utils import object_diff
label_desc: Use image node_id 1 for calling a global function with example usage: test_fine_cal_io(tmp_path, fname) without return types