code: def test_default_components():
      pca = KPCA()
      pca.fit(X1)
      assert pca.X_projected_.shape == X1.shape
  
file_path: mlxtend/mlxtend/feature_extraction/tests/test_kernel_pca.py
imports: import numpy
  import pytest
  from numpy.testing import assert_almost_equal
  from sklearn.datasets import make_moons
  from mlxtend.feature_extraction import RBFKernelPCA
label_desc: Use image node_id 1 for calling a global function with example usage: test_default_components() without return types