class_docstr: Single shared bias used in the Double DQN paper.
  
  You can add this link after a Linear layer with nobias=True to implement a
  Linear layer with a single shared bias parameter.
  
  See http://arxiv.org/abs/1509.06461.
code: def __call__(self, x):
      return x + F.broadcast_to(self.bias, x.shape)
  
imports: import argparse
  import functools
  import os
  import chainer
  from chainer import functions
  from chainer import links
  from chainer import optimizers
  import numpy
  import chainerrl
  from chainerrl.action_value import DiscreteActionValue
  from chainerrl import agents
  from chainerrl import experiments
  from chainerrl import explorers
  from chainerrl import links
  from chainerrl import misc
  from chainerrl.q_functions import DuelingDQN
  from chainerrl import replay_buffer
  from chainerrl.wrappers import atari_wrappers
label_desc: Use image node_id 2 for calling the SingleSharedBias obj's underlying member method code with example usage: obj.__call__(x) and returns: unknown