code: def K_diag(self, a_input: tf.Tensor) -> tf.Tensor:
      transformed_a = self.cnn(a_input)
      return self.base_kernel.K_diag(transformed_a)
  
file_path: GPflow/doc/sphinx/notebooks/tailor/gp_nn.pct.py
imports: from typing import Dict, Optional, Tuple
  import numpy
  import tensorflow
  import tensorflow_datasets
  from scipy.cluster.vq import kmeans2
  import gpflow
  from gpflow.ci_utils import reduce_in_tests
  from gpflow.utilities import to_default_float
label_desc: Use image node_id 3 for calling the KernelWithConvNN obj's underlying member method code with example usage: obj.K_diag(a_input) and returns: self