code: def test_get_buffer() -> None:
      s = pl.Series(["a", "bc", None, "éâç", ""])
  
      data = s._get_buffer(0)
      expected = pl.Series(
          [97, 98, 99, 195, 169, 195, 162, 195, 167], dtype=pl.UInt8
      )
      assert_series_equal(data, expected)
  
      validity = cast(pl.Series, s._get_buffer(1))
      expected = pl.Series([True, True, False, True, True])
      assert_series_equal(validity, expected)
  
      offsets = cast(pl.Series, s._get_buffer(2))
      expected = pl.Series([0, 1, 3, 3, 9, 9], dtype=pl.Int64)
      assert_series_equal(offsets, expected)
  
imports: from typing import cast
  import pytest
  import polars
  from polars.testing import assert_series_equal
label_desc: Use image node_id 1 for calling a global function with example usage: test_get_buffer() without return types