code: def test_one_cluster():
      """Test single cluster."""
  
      X = np.array([[1, 2], [10, 2], [10, 8]])
  
      bisect_means = BisectingKMeans(n_clusters=1, random_state=0).fit(
          X
      )
  
      # All labels from fit or predict should be equal 0
      assert all(bisect_means.labels_ == 0)
      assert all(bisect_means.predict(X) == 0)
  
      assert_allclose(
          bisect_means.cluster_centers_, X.mean(axis=0).reshape(1, -1)
      )
  
file_path: scikit-learn/sklearn/cluster/tests/test_bisect_k_means.py
imports: import numpy
  import pytest
  from sklearn.cluster import BisectingKMeans
  from sklearn.metrics import v_measure_score
  from sklearn.utils._testing import assert_allclose, assert_array_equal
  from sklearn.utils.fixes import CSR_CONTAINERS
label_desc: Use image node_id 4 for calling a global function with example usage: test_one_cluster() without return types