class_docstr: Hugging Face Llama Agent.
  
  LlamaForCausalLM is a multi-layer decoder-only Transformer.
  The decoder is initialized with pretrained weights from Hugging Face.
  Read more about this model here
  <https://huggingface.co/docs/transformers/main/model_doc/llama>.
docstr: Build and return model.
docstr_tok: ["Build","and","return","model","."]
code: def build_model(self, states=None):
      """
      Build and return model.
      """
      return ParlaiLlamaForCausalLM(self.opt, self.dict)
  
imports: from typing import Optional
  from parlai.core.params import ParlaiParser
  from parlai.core.opt import Opt
  import torch
  from parlai.agents.hugging_face.dict import LlamaDictionaryAgent, _init_llama_path
  from parlai.core.torch_generator_agent import TorchGeneratorAgent, TorchGeneratorModel
  from parlai.core.torch_classifier_agent import TorchClassifierAgent
  from parlai.utils.torch import IdentityLayer, padded_tensor
  from parlai.agents.transformer.transformer import _check_positional_embeddings
  import parlai.utils.logging
label_desc: Use image node_id 4 for calling the LlamaAgent obj's underlying member method code with example usage: obj.build_model(states) and returns: ParlaiLlamaForCausalLM