code: def test_get_chunks_from_col_chunks_single_chunk(
      allow_copy: bool,
  ) -> None:
      df = pl.DataFrame({"a": [1, 2, 3], "b": [4, 5, 6]})
  
      dfi = PolarsDataFrame(df, allow_copy=allow_copy)
      out = dfi._get_chunks_from_col_chunks()
  
      chunk1 = next(out)
      assert_frame_equal(chunk1, df)
  
      with pytest.raises(StopIteration):
          next(out)
  
imports: from __future__ import annotations
  import pytest
  import polars
  from polars.interchange.dataframe import PolarsDataFrame
  from polars.interchange.protocol import CopyNotAllowedError
  from polars.testing import assert_frame_equal, assert_series_equal
label_desc: Use image node_id 20 for calling a global function with example usage: test_get_chunks_from_col_chunks_single_chunk(allow_copy) without return types