code: def _huber_loss_1(a):
      if abs(a) < 1:
          return 0.5 * a**2
      else:
          return abs(a) - 0.5
  
imports: import unittest
  from chainer import testing
  import numpy
  import basetest_dqn_like
  import chainerrl
  from chainerrl.agents.dqn import compute_value_loss
  from chainerrl.agents.dqn import compute_weighted_value_loss
  from chainerrl.agents.dqn import DQN
  from basetest_training import _TestBatchTrainingMixin
label_desc: Use image node_id 1 for calling a global function with example usage: _huber_loss_1(a) and returns: unknown, unknown