code: def test_20_newsgroups():
      data = fetch_20newsgroups()
      X, y = data.data, data.target
      r = dask_ml.model_selection.train_test_split(X, y)
      X_train, X_test, y_train, y_test = r
      for X in [X_train, X_test]:
          assert isinstance(X, list)
          assert isinstance(X[0], str)
      for y in [y_train, y_test]:
          assert isinstance(y, np.ndarray)
          assert y.dtype == int
  
imports: import dask.array
  import dask.dataframe
  import numpy
  import pandas
  import pytest
  from sklearn.datasets import fetch_20newsgroups, make_regression
  import dask_ml.model_selection
  from dask_ml._compat import DASK_2130
label_desc: Use image node_id 1 for calling a global function with example usage: test_20_newsgroups() without return types