code: def parse_agent(agent):
      return {
          "DQN": agents.DQN,
          "DoubleDQN": agents.DoubleDQN,
          "PAL": agents.PAL,
      }[agent]
  
imports: import argparse
  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 a global function with example usage: parse_agent(agent) and returns: dict