code: def _rwb_pbroadcast_bwd(axis_name, _, cts):
      return (rwb_psum(cts, axis_name),)
  
imports: import collections
  import functools
  import tensorflow.compat.v2
  from tensorflow_probability.python.internal import custom_gradient
  from tensorflow_probability.python.internal import prefer_static
  from tensorflow_probability.python.internal import samplers
  from tensorflow.python.util import nest
label_desc: Use image node_id 16 for calling a global function with example usage: _rwb_pbroadcast_bwd(axis_name, _, cts) and returns: rwb_psum