code: def setUp(self):
      def evaluator(actions):
          # negative square norm of actions
          return -F.sum(actions**2, axis=1)
  
      self.evaluator = evaluator
  
      if self.has_maximizer:
  
          def maximizer():
              return chainer.Variable(
                  np.zeros(
                      (self.batch_size, self.action_size),
                      dtype=np.float32,
                  )
              )
  
      else:
          maximizer = None
      self.maximizer = maximizer
      self.av = action_value.SingleActionValue(
          evaluator=evaluator, maximizer=maximizer
      )
  
imports: import unittest
  import chainer
  import chainer.functions
  from chainer import testing
  import numpy
  from chainerrl import action_value
label_desc: Use image node_id 1 for calling the TestSingleActionValue obj's underlying member method code with example usage: obj.setUp() and returns: unknown, chainer