code: def forward(self, x):
      x = x[:, 0:1, ...] + self.drop_path(self.attn(self.norm1(x)))
      return x
  
imports: from functools import partial
  from typing import List
  from typing import Tuple
  import torch
  import torch.hub
  import torch.nn
  from timm.data import IMAGENET_DEFAULT_MEAN, IMAGENET_DEFAULT_STD
  from timm.layers import DropPath, to_2tuple, trunc_normal_, _assert
  from ._builder import build_model_with_cfg
  from ._features_fx import register_notrace_function
  from ._registry import register_model, generate_default_cfgs
  from .vision_transformer import Block
label_desc: Use image node_id 2 for calling the CrossAttentionBlock obj's underlying member method code with example usage: obj.forward(x) and returns: x