code: def forward(self, x):
      output = self.conva(x)
      output = self.a2block(output)
      output = self.convb(output)
      output = self.bottleneck(torch.cat([x, output], 1))
      return output
  
imports: import torch.nn
  import torch
  import torch.nn.functional
  from torch.nn import BatchNorm2d
label_desc: Use image node_id 2 for calling the GALDHead obj's underlying member method code with example usage: obj.forward(x) and returns: output