code: def _kahan_reduce_tangents(axis, primals, tangents):
      del primals  # unused
      doperands, _ = tangents
      reduced_tangent = tf.reduce_sum(doperands[0], axis)
      return (reduced_tangent, tf.zeros_like(reduced_tangent))
  
imports: import collections
  import functools
  import numpy
  import tensorflow.compat.v2
  from tensorflow_probability.python.internal import custom_gradient
  from tensorflow_probability.python.internal import distribute_lib
  from tensorflow_probability.python.internal import dtype_util
  from tensorflow_probability.python.internal import prefer_static
  from tensorflow_probability.python.internal import tensorshape_util
  from tensorflow_probability.python.internal import variadic_reduce
  from tensorflow_probability.python.math.scan_associative import scan_associative
  from tensorflow.python.util import deprecation
label_desc: Use image node_id 5 for calling a global function with example usage: _kahan_reduce_tangents(axis, primals, tangents) and returns: reduced_tangent,  tf