code: def forward(self, x: torch.Tensor) -> torch.Tensor:
      if self.down_flag:
          x = F.max_pool2d(x, kernel_size=2, stride=2, ceil_mode=True)
  
      return self.relu(self.bn(self.conv(x)))
  
imports: from typing import Union, List
  import torch
  import torch.nn
  import torch.nn.functional
label_desc: Use image node_id 2 for calling the DownConvBNReLU obj's underlying member method code with example usage: obj.forward(x) and returns: self