code: def prepare_item(self, context, length=256):
      tokens = self.tokenizer.encode(context)
      logger.info(tokens)
      token_length = len(tokens)
      pad_amount = self.params["seq"] - token_length
      pad_amount = max(pad_amount, 0)
      padded_tokens = np.pad(tokens, ((pad_amount, 0),)).astype(
          np.uint32
      )[-self.params["seq"] :]
      return {"tokens": padded_tokens, "length": token_length}
  
imports: import os
  import time
  import jax
  import optax
  import threading
  import numpy
  import logging
  from queue import Queue, Empty
  from jax.experimental import maps
  from transformers import GPT2TokenizerFast
  from mesh_transformer.checkpoint import read_ckpt
  from mesh_transformer.sampling import nucleaus_sample
  from mesh_transformer.transformer_shard import CausalTransformer
label_desc: Use image node_id 4 for calling the GPTJ obj's underlying member method code with example usage: obj.prepare_item(context, length) and returns: dict