code: def test_keyboard_interrupt():
      iris = load_iris()
      X = iris.data
      y = iris.target
  
      knn = KNeighborsClassifier(n_neighbors=4)
      sfs1 = SFS(
          knn,
          k_features=2,
          forward=True,
          floating=False,
          cv=3,
          clone_estimator=False,
          verbose=5,
          n_jobs=1,
          feature_groups=[[0, 1], [2], [3]],
      )
  
      sfs1._TESTING_INTERRUPT_MODE = True
      out = sfs1.fit(X, y)
  
      assert len(out.subsets_.keys()) > 0
      assert sfs1.interrupted_
  
imports: import numpy
  from numpy.testing import assert_almost_equal
  from sklearn.datasets import load_iris
  from sklearn.ensemble import RandomForestClassifier
  from sklearn.linear_model import LinearRegression
  from sklearn.metrics import roc_auc_score
  from sklearn.neighbors import KNeighborsClassifier
  from mlxtend.data import boston_housing_data
  from mlxtend.feature_selection import SequentialFeatureSelector
  from mlxtend.utils import assert_raises
label_desc: Use image node_id 7 for calling a global function with example usage: test_keyboard_interrupt() without return types