code: def forward(self, x, H, W):
      x = x + self.drop_path(self.gamma1 * self.attn(self.norm1(x)))
      x = x + self.drop_path(
          self.gamma3 * self.local_mp(self.norm3(x), H, W)
      )
      x = x + self.drop_path(self.gamma2 * self.mlp(self.norm2(x)))
      return x
  
imports: import logging
  import math
  from functools import partial
  from typing import List, Optional
  import torch
  import torch.nn
  from fairscale.nn import checkpoint_wrapper
  from vissl.config import AttrDict
  from vissl.models.model_helpers import DropPath, to_2tuple, trunc_normal_
  from vissl.models.trunks import register_model_trunk
  from vissl.models.trunks.vision_transformer import Mlp
  from vissl.utils.fsdp_utils import fsdp_wrapper
  from vissl.utils.misc import set_torch_seed
label_desc: Use image node_id 2 for calling the XCABlock obj's underlying member method code with example usage: obj.forward(x, H, W) and returns: x