code: def test_cast_inner() -> None:
      a = pl.Series([[1, 2]])
      for t in [bool, pl.Boolean]:
          b = a.cast(pl.List(t))
          assert b.dtype == pl.List(pl.Boolean)
          assert b.to_list() == [[True, True]]
  
      # this creates an inner null type
      df = pl.from_pandas(
          pd.DataFrame(data=[[[]], [[]]], columns=["A"])
      )
      assert (
          df["A"].cast(pl.List(int)).dtype.inner == pl.Int64  # type: ignore[attr-defined]
      )
  
imports: from __future__ import annotations
  import pickle
  from datetime import date, datetime, time
  from typing import TYPE_CHECKING, Any
  import pandas
  import pytest
  import polars
  from polars.testing import assert_frame_equal, assert_series_equal
label_desc: Use image node_id 3 for calling a global function with example usage: test_cast_inner() without return types