code: def test_is_duplicated_lf() -> None:
      ldf = pl.LazyFrame({"a": [4, 1, 4]}).select(
          pl.col("a").is_duplicated()
      )
      assert_series_equal(
          ldf.collect()["a"], pl.Series("a", [True, False, True])
      )
  
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 8 for calling a global function with example usage: test_is_duplicated_lf() without return types