code: def test_names(self):
      correct_names = set(
          ["epoch_channel", "batch_channel", "odd_channel"]
      )
      self.assertEqual(
          set(get_channel_name_stems(self.df)), correct_names
      )
  
imports: import unittest
  import numpy
  import pandas
  from pandas.testing import assert_frame_equal
  from neptune.common.utils import align_channels_on_x, as_list, get_channel_name_stems, map_keys, map_values, merge_dataframes
  from tests.unit.neptune.legacy.random_utils import sort_df_by_columns
label_desc: Use image node_id 2 for calling the TestGetChannelNameStems obj's underlying member method code with example usage: obj.test_names() without return types