code: def test_unique_on_list_df() -> None:
      assert pl.DataFrame(
          {
              "a": [1, 2, 3, 4, 4],
              "b": [[1, 1], [2], [3], [4, 4], [4, 4]],
          }
      ).unique(maintain_order=True).to_dict(as_series=False) == {
          "a": [1, 2, 3, 4],
          "b": [[1, 1], [2], [3], [4, 4]],
      }
  
file_path: polars/py-polars/tests/unit/operations/unique/test_unique.py
imports: from __future__ import annotations
  from datetime import date
  import pytest
  import polars
  from polars.testing import assert_frame_equal, assert_series_equal
label_desc: Use image node_id 2 for calling a global function with example usage: test_unique_on_list_df() without return types