code: def test_replace_empty_mapping() -> None:
      df = pl.DataFrame(
          {"int": [None, 1, None, 3]}, schema={"int": pl.Int16}
      )
      mapping: dict[Any, Any] = {}
      result = df.select(pl.col("int").replace(mapping))
      assert_frame_equal(result, df)
  
imports: from __future__ import annotations
  import contextlib
  from typing import Any
  import pytest
  import polars
  from polars.exceptions import CategoricalRemappingWarning
  from polars.testing import assert_frame_equal, assert_series_equal
label_desc: Use image node_id 19 for calling a global function with example usage: test_replace_empty_mapping() without return types