code: def test_join_as_of_by_schema() -> None:
      a = pl.DataFrame({"a": [1], "b": [2], "c": [3]}).lazy()
      b = pl.DataFrame({"a": [1], "b": [2], "d": [4]}).lazy()
      q = a.join_asof(b, on=pl.col("a").set_sorted(), by="b")
      assert q.collect().columns == q.columns
  
imports: from __future__ import annotations
  from collections import OrderedDict
  from datetime import date, timedelta
  from typing import Any, Iterator, Mapping
  import pytest
  import polars
  from polars.testing import assert_frame_equal, assert_series_equal
label_desc: Use image node_id 12 for calling a global function with example usage: test_join_as_of_by_schema() without return types