code: def forward(self, img):
      x = self.to_patches(img)
  
      for transformer, downsample in self.layers:
          x = transformer(x)
  
          if exists(downsample):
              x = downsample(x)
  
      return self.mlp_head(x)
  
imports: from functools import partial
  import torch
  from torch import nn
  from einops import rearrange, repeat
  from einops.layers.torch import Rearrange, Reduce
label_desc: Use image node_id 2 for calling the ScalableViT obj's underlying member method code with example usage: obj.forward(img) and returns: self