class_docstr: Pre-activation version of the BasicBlock.
code: def forward(self, x):
      out = F.relu(self.bn1(x))
      shortcut = self.shortcut(out) if hasattr(self, "shortcut") else x
      out = self.conv1(out)
      out = self.conv2(F.relu(self.bn2(out)))
      out += shortcut
      return out
  
imports: import torch
  import torch.nn
  import torch.nn.functional
label_desc: Use image node_id 2 for calling the PreActBlock obj's underlying member method code with example usage: obj.forward(x) and returns: out