code: def _sample_n(self, n, seed=None):
      return tf.scan(
          lambda acc, x: self.a * acc + x,
          self.shocks._sample_n(n, seed),
      )
  
file_path: edward/tests/inferences/ar_process_test.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import edward
  import numpy
  import tensorflow
  from edward.models import Normal, PointMass
  from scipy.optimize import minimize
  from edward.models import RandomVariable
  from tensorflow.contrib.distributions import Distribution
  from tensorflow.contrib.distributions import FULLY_REPARAMETERIZED
label_desc: Use image node_id 3 for calling the AutoRegressive obj's underlying member method code with example usage: obj._sample_n(n, seed) and returns: tf