code: def build_hf_gpt_transformer(
      layers,
      model_dim,
      heads,
      max_mel_seq_len,
      max_text_seq_len,
      max_prompt_len,
      checkpointing,
  ):
      """
      GPT-2 implemented by the HuggingFace library.
      """
      from transformers import GPT2Config, GPT2Model
  
      gpt_config = GPT2Config(
          vocab_size=256,  # Unused.
          n_positions=max_mel_seq_len
          + max_text_seq_len
          + max_prompt_len,
          n_ctx=max_mel_seq_len + max_text_seq_len + max_prompt_len,
          n_embd=model_dim,
          n_layer=layers,
          n_head=heads,
          gradient_checkpointing=checkpointing,
          use_cache=not checkpointing,
      )
      gpt = GPT2Model(gpt_config)
      # Override the built in positional embeddings
      del gpt.wpe
      gpt.wpe = functools.partial(
          null_position_embeddings, dim=model_dim
      )
      # Built-in token embeddings are unused.
      del gpt.wte
  
      mel_pos_emb = (
          LearnedPositionEmbeddings(max_mel_seq_len, model_dim)
          if max_mel_seq_len != -1
          else functools.partial(
              null_position_embeddings, dim=model_dim
          )
      )
      text_pos_emb = (
          LearnedPositionEmbeddings(max_text_seq_len, model_dim)
          if max_mel_seq_len != -1
          else functools.partial(
              null_position_embeddings, dim=model_dim
          )
      )
      # gpt = torch.compile(gpt, mode="reduce-overhead", fullgraph=True)
      return gpt, mel_pos_emb, text_pos_emb, None, None
  
imports: import functools
  import math
  import random
  import torch
  import torch.nn
  import torch.nn.functional
  from transformers import GPT2Config
  from TTS.tts.layers.xtts.gpt_inference import GPT2InferenceModel
  from TTS.tts.layers.xtts.latent_encoder import ConditioningEncoder
  from TTS.tts.layers.xtts.perceiver_encoder import PerceiverResampler
label_desc: Use image node_id 2 for calling a global function with example usage: build_hf_gpt_transformer(layers, model_dim, heads, max_mel_seq_len, max_text_seq_len, max_prompt_len, checkpointing) and returns: gpt,  mel_pos_emb,  text_pos_emb,  None,  None