code: def test_is_unique() -> None:
      df = pl.DataFrame({"foo": [1, 2, 2], "bar": [6, 7, 7]})
  
      assert_series_equal(
          df.is_unique(), pl.Series("", [True, False, False])
      )
      assert df.unique(maintain_order=True).rows() == [(1, 6), (2, 7)]
      assert df.n_unique() == 2
  
file_path: polars/py-polars/tests/unit/operations/unique/test_is_unique.py
imports: import polars
  from polars.testing import assert_series_equal
label_desc: Use image node_id 2 for calling a global function with example usage: test_is_unique() without return types