code: def test_get_validity_buffer_no_nulls() -> None:
      s = pl.Series([1.0, 3.0, 2.0])
      col = PolarsColumn(s)
  
      assert col._get_validity_buffer() is None
  
imports: from __future__ import annotations
  from datetime import datetime
  from typing import TYPE_CHECKING
  import pytest
  import polars
  from polars.interchange.column import PolarsColumn
  from polars.interchange.protocol import ColumnNullType, CopyNotAllowedError, DtypeKind
  from polars.testing import assert_series_equal
label_desc: Use image node_id 24 for calling a global function with example usage: test_get_validity_buffer_no_nulls() without return types