code: def test_tfr_ctf():
      """Test that TFRs can be calculated on CTF data."""
      raw = read_raw_fif(raw_ctf_fname).crop(0, 1)
      raw.apply_gradient_compensation(3)
      events = mne.make_fixed_length_events(raw, duration=0.5)
      epochs = mne.Epochs(raw, events)
      for method in (tfr_multitaper, tfr_morlet):
          method(epochs, [10], 1)
  
imports: import datetime
  import re
  from itertools import product
  from pathlib import Path
  import matplotlib.pyplot
  import numpy
  import pytest
  from numpy.testing import assert_allclose, assert_array_equal, assert_equal
  from scipy.signal import morlet2
  import mne
  from mne import Epochs, EpochsArray, Info, Transform, create_info, pick_types, read_events
  from mne.io import read_raw_fif
  from mne.tests.test_epochs import assert_metadata_equal
  from mne.time_frequency import tfr_array_morlet, tfr_array_multitaper
  from mne.time_frequency.tfr import AverageTFR, EpochsTFR, _compute_tfr, _make_dpss, combine_tfr, cwt, fwhm, morlet, read_tfrs, tfr_morlet, tfr_multitaper, write_tfrs
  from mne.utils import catch_logging, grand_average
  from mne.viz.utils import _fake_click, _fake_keypress, _fake_scroll
label_desc: Use image node_id 1 for calling a global function with example usage: test_tfr_ctf() without return types