new_contents: import torch.nn as nn
  import torch.nn.functional as F
  
  class Atari_2600(nn.Module):
      """Reseau convolutionnel:
          taille de l'input 4*84*84
          conv 1 32*20*20
          conv 2 64*9*9
          conv 3 64*7*7
          lin1 3136 -> 512
          lin2 512 -> nb actions
          Piste d'amélioration : DropOut, BatchNorm, Dueling Network, ResNet """
      def __init__(self,nb_actions):
          super(Atari_2600,self).__init__()
          self.conv1 = nn.Conv2d(4,32, kernel_size=8,stride=4,padding=1)
          #self.bn1 = nn.BatchNorm2d(16)
          self.conv2 = nn.Conv2d(32,64, kernel_size=4,stride=2)
          #self.bn2 = nn.BatchNorm2d(32)
          self.conv3 = nn.Conv2d(64,64, kernel_size=3,stride=1)
          #self.bn3 = nn.BatchNorm2d(32)
          self.linear = nn.Linear(3136,512)
          self.head = nn.Linear(512,nb_actions)
          self.name = "dqn"
  
      def forward(self,x):
          x = F.relu(self.conv1(x))
          x = F.relu(self.conv2(x))
          x = F.relu(self.conv3(x))
          x = x.view(x.size(0),-1)
          x = F.relu(self.linear(x))
          return self.head(x)
  
subject: Create NetworkAtari.py