code: def categorical_loss(y, t):
      return -t * np.log(np.clip(y, 1e-10, 1.0))
  
imports: import unittest
  import basetest_dqn_like
  import numpy
  import pytest
  import torch
  from basetest_training import _TestBatchTrainingMixin
  import pfrl
  from pfrl.agents import CategoricalDQN, categorical_dqn
  from pfrl.agents.categorical_dqn import compute_value_loss, compute_weighted_value_loss
label_desc: Use image node_id 4 for calling a global function with example usage: categorical_loss(y, t) and returns: unknown