code: def build_operator(self):
      return tf.linalg.LinearOperatorBlockDiag(
          [
              tf.linalg.LinearOperatorDiag(diag=[2.0, 3.0, 6.0]),
              tf.linalg.LinearOperatorFullMatrix(
                  matrix=[[12.0, 5.0], [-1.0, 3.0]]
              ),
          ],
          is_non_singular=True,
      )
  
imports: import numpy
  import tensorflow.compat.v2
  from tensorflow_probability.python.bijectors import scale_matvec_linear_operator
  from tensorflow_probability.python.internal import test_util
label_desc: Use image node_id 1 for calling the ScaleMatvecLinearOperatorBlockDiagTest obj's underlying member method code with example usage: obj.build_operator() and returns: tf