code: def forward(self, x):
      x = self.norm(x)
      sim = torch.matmul(self.queries, x.transpose(-1, -2)) * self.scale
      attn = sim.softmax(dim=-1)
      return torch.matmul(attn, x)
  
imports: 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 PatchMerger obj's underlying member method code with example usage: obj.forward(x) and returns: torch