code: def forward(
      self,
      query,
      key,
      value,
      need_weights: bool = None,
      key_padding_mask: Optional[Tensor] = None,
      incremental_state: Optional[Dict[str, Tensor]] = None,
  ) -> Tuple[Tensor, Optional[Tensor]]:
      optional_attention: Optional[Tensor] = None
      return query, optional_attention
  
imports: from typing import Dict, Optional, Tuple
  from pytext.config.module_config import ModuleConfig
  from pytext.models.module import Module
  from pytext.utils.usage import log_class_usage
  from torch import nn, Tensor
  from .utils import prepare_full_key
label_desc: Use image node_id 1 for calling the PlaceholderAttentionIdentity obj's underlying member method code with example usage: obj.forward(query, key, value, need_weights, key_padding_mask, incremental_state) and returns: query,  optional_attention