code: def test_expand_event_series_no_freq():
      expanded_events = expand_events(
          event_labels,
          left_expand="1hour",
          right_expand="1hour",
          freq_as_period=False,
      )
      pd.testing.assert_series_equal(
          event_labels, expanded_events, check_dtype=False
      )
  
file_path: adtk/tests/test_expand_events.py
imports: import pandas
  from adtk.data import expand_events
label_desc: Use image node_id 2 for calling a global function with example usage: test_expand_event_series_no_freq() without return types