code: def assert_suppressed(new, old, suppressed, retained):
      """Assert that some frequencies are suppressed and others aren't."""
      __tracebackhide__ = True
      from scipy.signal import welch
  
      picks = pick_types(new.info, meg="grad")
      sfreq = new.info["sfreq"]
      new = new.get_data(picks)
      old = old.get_data(picks)
      f, new = welch(new, sfreq, "hann", nperseg=1024)
      _, old = welch(old, sfreq, "hann", nperseg=1024)
      new = np.median(new, axis=0)
      old = np.median(old, axis=0)
      for freqs, lim in ((suppressed, (10, 60)), (retained, (-3, 3))):
          for freq in freqs:
              fidx = np.argmin(np.abs(f - freq))
              this_new = np.median(new[fidx])
              this_old = np.median(old[fidx])
              suppression = -10 * np.log10(this_new / this_old)
              assert lim[0] < suppression < lim[1], freq
  
imports: from pathlib import Path
  import numpy
  import pytest
  from numpy.testing import assert_allclose, assert_array_equal, assert_array_less
  from scipy.interpolate import interp1d
  from scipy.spatial.distance import cdist
  from mne import pick_info, pick_types
  from mne._fiff.constants import FIFF
  from mne.chpi import _chpi_locs_to_times_dig, _compute_good_distances, _get_hpi_initial_fit, _setup_ext_proj, compute_chpi_amplitudes, compute_chpi_locs, compute_chpi_snr, compute_head_pos, extract_chpi_locs_ctf, extract_chpi_locs_kit, filter_chpi, get_active_chpi, get_chpi_info, head_pos_to_trans_rot_t, read_head_pos, write_head_pos
  from mne.datasets import testing
  from mne.forward._compute_forward import _MAG_FACTOR
  from mne.io import RawArray, read_info, read_raw_artemis123, read_raw_ctf, read_raw_fif, read_raw_kit
  from mne.simulation import add_chpi
  from mne.transforms import _angle_between_quats, rot_to_quat
  from mne.utils import assert_meg_snr, catch_logging, object_diff, verbose
  from mne.viz import plot_head_positions
label_desc: Use image node_id 19 for calling a global function with example usage: assert_suppressed(new, old, suppressed, retained) without return types