code: def get_log_rhos(target_action_log_probs, behaviour_action_log_probs):
      """With the selected log_probs for multi-discrete actions of behaviour
      and target policies we compute the log_rhos for calculating the vtrace.
      """
      t = tf.stack(target_action_log_probs)
      b = tf.stack(behaviour_action_log_probs)
      log_rhos = tf.reduce_sum(t - b, axis=0)
      return log_rhos
  
file_path: ray/python/ray/rllib/algorithms/impala/vtrace_tf.py
imports: import collections
  from ray.rllib.models.tf.tf_action_dist import Categorical
  from ray.rllib.utils.framework import try_import_tf
label_desc: Use image node_id 6 for calling a global function with example usage: get_log_rhos(target_action_log_probs, behaviour_action_log_probs) and returns: log_rhos