code: def decision_function(self, X):
      K = rbf_kernel(X, self.X_train_, gamma=self.gamma)
      return super().decision_function(K)
  
file_path: lightning/examples/plot_sparse_non_linear.py
imports: import numpy
  import pylab
  from sklearn.metrics.pairwise import rbf_kernel
  from lightning.classification import CDClassifier
  from lightning.classification import KernelSVC
label_desc: Use image node_id 3 for calling the SparseNonlinearClassifier obj's underlying member method code with example usage: obj.decision_function(X) and returns: super