code: def test_single_model_pool(create_X_y):
      X, y = create_X_y
      pool = [DecisionTreeClassifier().fit(X, y)]
      with pytest.raises(ValueError):
          StackedClassifier(pool_classifiers=pool).fit(X, y)
  
file_path: DESlib/deslib/tests/static/test_stacked.py
imports: import numpy
  import pytest
  from sklearn.datasets import make_classification
  from sklearn.linear_model import Perceptron
  from sklearn.tree import DecisionTreeClassifier
  from sklearn.utils.estimator_checks import check_estimator
  from deslib.static.stacked import StackedClassifier
label_desc: Use image node_id 9 for calling a global function with example usage: test_single_model_pool(create_X_y) without return types