code: def prepare_inputs_for_generation(
      self, input_ids, past=None, use_cache=None, **kwargs
  ):
      # only last token for inputs_ids if past is defined in kwargs
      if past:
          input_ids = input_ids[:, -1].unsqueeze(-1)
  
      return {
          "input_ids": input_ids,
          "past_key_values": past,
          "use_cache": use_cache,
      }
  
imports: from typing import Optional, Tuple, Union
  import numpy
  import torch
  from torch import nn
  from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, MSELoss
  from ...modeling_outputs import BaseModelOutputWithPast, CausalLMOutputWithPast, SequenceClassifierOutput
  from ...modeling_utils import PreTrainedModel
  from ...pytorch_utils import Conv1D, find_pruneable_heads_and_indices, prune_linear_layer
  from ...utils import add_start_docstrings, add_start_docstrings_to_model_forward, logging, replace_return_docstrings
  from .configuration_ctrl import CTRLConfig
label_desc: Use image node_id 4 for calling the CTRLLMHeadModel obj's underlying member method code with example usage: obj.prepare_inputs_for_generation(input_ids, past, use_cache) and returns: dict