class_docstr: Relative positional encoding for TransformerXL's layers
  See : Appendix B in https://arxiv.org/abs/1901.02860
  
  .. note::
  
      Relative positional embedding value is **not** added to the input tensor !
      Therefore, the input should be updated changed, if you only require the positional embedding, drop the returned `x` !
  
  Args:
      d_model (int): embedding dim
      max_len (int): maximum input length
      xscale (bool): whether to scale the input by sqrt(d_model)
      adapter_strategy: By default, ReturnResultAdapterStrategyConfig. An adapter composition function object.
code: def get_default_strategy_config(self) -> "dataclass":
      return (
          adapter_mixin_strategies.ReturnResultAdapterStrategyConfig()
      )
  
imports: import math
  from dataclasses import dataclass, field
  from typing import Any, Optional
  import torch
  from torch import nn
  from nemo.collections.asr.parts.submodules import multi_head_attention
  from nemo.collections.common.parts import adapter_modules
  from nemo.core.classes.mixins import adapter_mixin_strategies
label_desc: Use image node_id 2 for calling the RelPositionalEncodingAdapter obj's underlying member method code with example usage: obj.get_default_strategy_config() and returns: adapter_mixin_strategies