class_docstr: Lunar Causal attention.
  See "Linformer: Self-Attention with Linear Complexity" for more details.
code: def _set_input_buffer(
      self,
      incremental_state: Dict[str, Dict[str, Optional[Tensor]]],
      buffer: Dict[str, Optional[Tensor]],
  ):
      return self.set_incremental_state(
          incremental_state, "attn_state", buffer
      )
  
imports: import math
  from typing import Dict, Optional, Tuple, Union
  import torch
  import torch.nn.functional
  from fairseq import utils
  from fairseq.incremental_decoding_utils import with_incremental_state
  from fairseq.modules.fairseq_dropout import FairseqDropout
  from torch import nn, Tensor
label_desc: Use image node_id 9 for calling the LunarCausalAttention obj's underlying member method code with example usage: obj._set_input_buffer(incremental_state, buffer) and returns: self