code: def compute_importance(pi, mu, x):
      return np.nan_to_num(
          float(pi.prob(x).array) / float(mu.prob(x).array)
      )
  
imports: import copy
  from logging import getLogger
  import chainer
  from chainer import functions
  import numpy
  from chainerrl.action_value import SingleActionValue
  from chainerrl import agent
  from chainerrl import distribution
  from chainerrl import links
  from chainerrl.misc import async_
  from chainerrl.misc import copy_param
  from chainerrl.recurrent import Recurrent
  from chainerrl.recurrent import RecurrentChainMixin
  from chainerrl.recurrent import state_kept
  from chainerrl.recurrent import state_reset
label_desc: Use image node_id 1 for calling a global function with example usage: compute_importance(pi, mu, x) and returns: np