code: def test_std_err(df):
      """
      Test the standard error of the mean matches result from scipy.stats.sem
      """
      np.testing.assert_allclose(
          Description(df["a"]).frame.loc["std_err"],
          scipy.stats.sem(df["a"]),
      )
  
file_path: statsmodels/statsmodels/stats/tests/test_descriptivestats.py
imports: import numpy
  from numpy.testing import assert_almost_equal, assert_equal
  import pandas
  import scipy.stats
  import pytest
  from statsmodels.iolib.table import SimpleTable
  from statsmodels.stats.descriptivestats import Description, describe, sign_test
label_desc: Use image node_id 11 for calling a global function with example usage: test_std_err(df) without return types