code: def forward(self, q_values):
      return DiscreteActionValue(q_values)
  
imports: import numpy
  import torch
  import torch.nn
  import torch.nn.functional
  from pfrl.action_value import DiscreteActionValue, DistributionalDiscreteActionValue, QuadraticActionValue
  from pfrl.functions.lower_triangular_matrix import lower_triangular_matrix
  from pfrl.initializers import init_chainer_default
  from pfrl.nn import Lambda
  from pfrl.nn.mlp import MLP
  from pfrl.q_function import StateQFunction
label_desc: Use image node_id 1 for calling the DiscreteActionValueHead obj's underlying member method code with example usage: obj.forward(q_values) and returns: DiscreteActionValue