code: def is_stationary(self):
      return np.all([kernel.is_stationary() for kernel in self.kernels])
  
imports: import random
  import os
  import sys
  import collections
  import itertools
  import pickle
  import scipy.sparse
  import networkx
  import numpy
  from sklearn.cluster import SpectralClustering
  from sklearn import gaussian_process
  from scipy.optimize import minimize
  from bayes_opt import BayesianOptimization
label_desc: Use image node_id 4 for calling the K obj's underlying member method code with example usage: obj.is_stationary() and returns: np