code: def test_non_empty_map(self):
      # when
      mapped_dict = map_keys(times_2, {2: "a", 3: "b"})
  
      # then
      self.assertEqual({4: "a", 6: "b"}, mapped_dict)
  
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 TestMapKeys obj's underlying member method code with example usage: obj.test_non_empty_map() without return types