code: def test_slice1(dates):
      """Test output of slice on index."""
      expected = dates.select_rows(slice(None, None))
      assert_frame_equal(expected, dates, check_freq=False)
  
imports: import datetime
  import re
  import numpy
  import pandas
  import pytest
  from pandas.testing import assert_frame_equal
label_desc: Use image node_id 20 for calling a global function with example usage: test_slice1(dates) without return types