code: def test_to_data_frame_time_format(time_format):
      """Test time conversion in evoked Pandas exporter."""
      pd = pytest.importorskip("pandas")
      ave = read_evokeds(fname, 0)
      # test time_format
      df = ave.to_data_frame(time_format=time_format)
      dtypes = {
          None: np.float64,
          "ms": np.int64,
          "timedelta": pd.Timedelta,
      }
      assert isinstance(df["time"].iloc[0], dtypes[time_format])
  
imports: import pickle
  from copy import deepcopy
  from pathlib import Path
  import numpy
  import pytest
  from numpy.testing import assert_allclose, assert_array_almost_equal, assert_array_equal, assert_equal
  from scipy import fftpack
  from mne import Epochs, EpochsArray, combine_evoked, create_info, equalize_channels, pick_types, read_events, read_evokeds, write_evokeds
  from mne._fiff.constants import FIFF
  from mne.evoked import Evoked, EvokedArray, _get_peak
  from mne.io import read_raw_fif
  from mne.utils import grand_average
label_desc: Use image node_id 15 for calling a global function with example usage: test_to_data_frame_time_format(time_format) without return types