code: def _matmul_a_b_at(a, b):
      """Calculate `A @ B @ transpose(A)`."""
      return tf.matmul(a, tf.matmul(b, a, transpose_b=True))
  
file_path: probability/tensorflow_probability/python/experimental/sequential/extended_kalman_filter.py
imports: import functools
  import tensorflow.compat.v2
  from tensorflow_probability.python.distributions import independent
  from tensorflow_probability.python.distributions import linear_gaussian_ssm
  from tensorflow_probability.python.distributions import mvn_tril
  from tensorflow_probability.python.distributions import normal
  from tensorflow_probability.python.internal import prefer_static
  from tensorflow_probability.python.math import linalg
  from tensorflow.python.util import nest
label_desc: Use image node_id 3 for calling a global function with example usage: _matmul_a_b_at(a, b) and returns: tf