code: def apply_pos_bias(self, fmap):
      bias = self.pos_bias(self.pos_indices)
      bias = rearrange(bias, "i j h -> () h i j")
      return fmap + (bias / self.scale)
  
imports: from math import ceil
  import torch
  from torch import nn, einsum
  import torch.nn.functional
  from einops import rearrange, repeat
  from einops.layers.torch import Rearrange
label_desc: Use image node_id 2 for calling the Attention obj's underlying member method code with example usage: obj.apply_pos_bias(fmap) and returns: unknown