code: def test_apply_no_grouper(df):
      df = df[["x", "y"]]
      res = GroupBy(["a"]).apply(df, lambda x: x.sort_values("x"))
      assert_array_equal(res.columns, ["x", "y"])
      assert_array_equal(res["x"], df["x"].sort_values())
      assert_array_equal(res["y"], df.loc[np.argsort(df["x"]), "y"])
  
file_path: seaborn/tests/_core/test_groupby.py
imports: import numpy
  import pandas
  import pytest
  from numpy.testing import assert_array_equal
  from seaborn._core.groupby import GroupBy
label_desc: Use image node_id 9 for calling a global function with example usage: test_apply_no_grouper(df) without return types