class_docstr: Relative Position Bias
  Adapted from Swin-V1 relative position bias impl, modularized.
class_docstr_tok: ["Relative","Position","Bias","Adapted","from","Swin-V1","relative","position","bias","impl",",","modularized","."]
code: def forward(
      self, attn, shared_rel_pos: Optional[torch.Tensor] = None
  ):
      return attn + self.get_bias()
  
imports: import math
  import os
  from typing import Optional, Tuple
  import torch
  import torch.nn
  import torch.nn.functional
  from .interpolate import RegularGridInterpolator
  from .mlp import Mlp
  from .weight_init import trunc_normal_
label_desc: Use image node_id 4 for calling the RelPosBias obj's underlying member method code with example usage: obj.forward(attn, shared_rel_pos) and returns: unknown