code: def test_binary_conversions() -> None:
      df = pl.DataFrame({"blob": [b"abc", None, b"cde"]}).with_columns(
          pl.col("blob").cast(pl.String).alias("decoded_blob")
      )
  
      assert df.to_dict(as_series=False) == {
          "blob": [b"abc", None, b"cde"],
          "decoded_blob": ["abc", None, "cde"],
      }
      assert df[0, 0] == b"abc"
      assert df[1, 0] is None
      assert df.dtypes == [pl.Binary, pl.String]
  
file_path: polars/py-polars/tests/unit/namespaces/test_binary.py
imports: import pytest
  import polars
  from polars.testing import assert_frame_equal
  from polars.type_aliases import TransferEncoding
label_desc: Use image node_id 1 for calling a global function with example usage: test_binary_conversions() without return types